Corticosteroids for the treatment of joint pain

ABSTRACT

Corticosteroid microparticle formulations are provided for use for treating pain, including pain caused by inflammatory diseases such as osteoarthritis or rheumatoid arthritis, and for slowing, arresting or reversing structural damage to tissues caused by an inflammatory disease, for example damage to articular and/or peri-articular tissues caused by osteoarthritis or rheumatoid arthritis. Corticosteroid microparticle formulations are administered locally as a sustained release dosage form (with or without an immediate release component) that results in efficacy accompanied by clinically insignificant or no measurable effect on endogenous cortisol production.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/461,884, filed Aug. 18, 2014 and issued as U.S. Pat. No. 9,555,048,which is a divisional of U.S. patent application Ser. No. 13/422,994,filed Mar. 16, 2012 and issued as U.S. Pat. No. 8,828,440, which is acontinuation of U.S. patent application Ser. No. 13/198,168, filed Aug.4, 2011, which claims the benefit of U.S. Provisional Application No.61/370,666, filed Aug. 4, 2010, and this application is a continuationof U.S. patent application Ser. No. 14/461,883, filed Aug. 18, 2014 andissued as U.S. Pat. No. 9,555,047, which is a divisional of U.S. patentapplication Ser. No. 13/422,994, filed Mar. 16, 2012 and issued as U.S.Pat. No. 8,828,440, which is a continuation of U.S. patent applicationSer. No. 13/198,168, filed Aug. 4, 2011, which claims the benefit ofU.S. Provisional Application No. 61/370,666, filed Aug. 4, 2010. Thecontents of these applications are hereby incorporated by reference intheir entireties.

FIELD OF THE INVENTION

This invention relates to the use of corticosteroids to treat pain,including pain caused by inflammatory diseases such as osteoarthritis orrheumatoid arthritis, and to slow, arrest or reverse structural damageto tissues caused by an inflammatory disease, for example damage toarticular and/or peri-articular tissues caused by osteoarthritis orrheumatoid arthritis. More specifically, a corticosteroid isadministered locally as a sustained release dosage form (with or withoutan immediate release component) that results in efficacy accompanied byclinically insignificant or no measurable effect on endogenous cortisolproduction.

BACKGROUND OF THE INVENTION

Corticosteroids influence all tissues of the body and produce variouscellular effects. These steroids regulate carbohydrate, lipid, proteinbiosynthesis and metabolism, and water and electrolyte balance.Corticosteroids influencing cellular biosynthesis or metabolism arereferred to as glucocorticoids while those affecting water andelectrolyte balance are mineralocorticoids. Both glucocorticoids andmineralocorticoids are released from the cortex of the adrenal gland.

The administration of corticosteroids, particularly for extended periodsof time, can have a number of unwanted side effects. The interdependentfeedback mechanism between the hypothalamus, which is responsible forsecretion of corticotrophin-releasing factor, the pituitary gland, whichis responsible for secretion of adrenocorticotropic hormone, and theadrenal cortex, which secretes cortisol, is termed thehypothalamic-pituitary-adrenal (HPA) axis. The HPA axis may besuppressed by the administration of corticosteroids, leading to avariety of unwanted side effects.

Accordingly, there is a medical need to extend the local duration ofaction of corticosteroids, while reducing the systemic side effectsassociated with that administration. Thus, there is a need in the artfor methods and compositions for the sustained local treatment of painand inflammation, such as joint pain, with corticosteroids that resultsin clinically insignificant or no measurable HPA axis suppression. Inaddition, there is a medical need to slow, arrest, reverse or otherwiseinhibit structural damage to tissues caused by inflammatory diseasessuch as damage to articular tissues resulting from osteoarthritis orrheumatoid arthritis.

SUMMARY OF THE INVENTION

Described herein are compositions and methods for the treatment of painand inflammation using corticosteroids. The compositions and methodsprovided herein use one or more corticosteroids in a microparticleformulation. The corticosteroid microparticle formulations providedherein are effective at treating pain and/or inflammation with minimallong-term side effects of corticosteroid administration, including forexample, prolonged suppression of the HPA axis. The corticosteroidmicroparticle formulations are suitable for administration, for example,local administration by injection into a site at or near the site of apatient's pain and/or inflammation. The corticosteroid microparticleformulations provided herein are effective in slowing, arresting,reversing or otherwise inhibiting structural damage to tissuesassociated with progressive disease with minimal long-term side effectsof corticosteroid administration, including for example, prolongedsuppression of the HPA axis. The corticosteroid microparticleformulations are suitable for administration, for example, localadministration by injection into a site at or near the site ofstructural tissue damage. As used herein, “prolonged” suppression of theHPA axis refers to levels of cortisol suppression greater than 35% byday 14 post-administration, for example post-injection. Thecorticosteroid microparticle formulations provided herein deliver thecorticosteroid in a dose and in a controlled or sustained release mannersuch that the levels of cortisol suppression are at or below 35% by day14 post-administration, for example post-injection. In some embodiments,the corticosteroid microparticle formulations provided herein deliverthe corticosteroid in a dose and in a controlled or sustained releasemanner such that the levels of cortisol suppression are negligibleand/or undetectable by 14 post-administration, for examplepost-injection. In some embodiments, the corticosteroid microparticleformulations provided herein deliver the corticosteroid in a dose and ina controlled or sustained release manner such that the levels ofcortisol suppression are negligible at any time post-injection. Thus,the corticosteroid microparticle formulations in these embodiments areeffective in the absence of any significant HPA axis suppression.Administration of the corticosteroid microparticle formulations providedherein can result in an initial “burst” of HPA axis suppression, forexample, within the first few days, within the first two days and/orwithin the first 24 hours post-injection, but by day 14 post-injection,suppression of the HPA axis is less than 35%.

In certain embodiments, a sustained release form of corticosteroids isadministered locally to treat pain and inflammation. Localadministration of a corticosteroid microparticle formulation can occur,for example, by injection into the intra-articular space, peri-articularspace, soft tissues, lesions, epidural space, perineural space, or theforamenal space at or near the site of a patient's pain. In certainembodiments, the formulation additionally contains an immediate releasecomponent. In certain preferred embodiments of the invention, asustained release form of corticosteroids is administered (e.g., bysingle injection or as sequential injections) into an intra-articularspace for the treatment of pain, for example, due to osteoarthritis,rheumatoid arthritis, gouty arthritis, bursitis, tenosynovitis,epicondylitis, synovitis or other joint disorder. In certain preferredembodiments of the invention, a sustained release form ofcorticosteroids is administered (e.g., by single injection or assequential injections) into soft tissues or lesions for the treatment ofinflammatory disorders, for example, the inflammatory and pruriticmanifestations of corticosteroid-responsive dermatoses such aspsoriasis. In certain preferred embodiments of the invention, asustained release form of corticosteroids is administered (e.g., bysingle injection or as sequential injections) into an epidural space, aperineural space, a foramenal space or other spinal space for thetreatment of corticosteroid-responsive degenerative musculoskeletaldisorders such as Neurogenic Claudication. In certain preferredembodiments of the invention, a sustained release form ofcorticosteroids is administered (e.g., by single injection or assequential injections) into an intra-articular space or into softtissues to slow, arrest, reverse or otherwise inhibit structural damageto tissues associated with progressive disease such as, for example, thedamage to cartilage associated with progression of osteoarthritis.

In certain embodiments of the invention, a combination of an immediaterelease form and a sustained release form of corticosteroids isadministered (e.g., by single injection or as sequential injections)into an intra-articular space for the treatment of pain, for example,due to osteoarthritis, rheumatoid arthritis or other joint disorder(s).In certain embodiments of the invention, a combination of an immediaterelease form and a sustained release form of corticosteroids isadministered (e.g., by single injection or as sequential injections)into an intra-articular space or into soft tissues to slow, arrest,reverse or otherwise inhibit structural damage to tissues associatedwith progressive disease such as, for example, the damage to cartilageassociated with progression of osteoarthritis. The formulations andmethods of embodiments of the invention can achieve immediate relief ofthe acute symptoms (e.g., pain and inflammation) of these diseases orconditions and additionally provide a sustained or long term therapy(e.g., slowing, arresting, reversing or otherwise inhibiting structuraldamage to tissues associated with progressive disease), while avoidinglong term systemic side effects associated with corticosteroidadministration, including HPA suppression.

In one aspect, a formulation is provided wherein a microparticle matrix(such as PLGA, PLA, hydrogels, hyaluronic acid, etc.) incorporates acorticosteroid, and the corticosteroid microparticle formulationprovides at least two weeks, preferably at least three weeks, includingup to and beyond 30 days, or 60 days, or 90 days of a sustained, steadystate release of the corticosteroid. In one aspect, a formulation isprovided wherein a microparticle matrix (such as PLGA, PLA, hydrogels,hyaluronic acid, etc.) incorporates a corticosteroid, and thecorticosteroid microparticle formulation provides at least two weeks,preferably at least three weeks, including up to and beyond 30 days, or60 days, or 90 days of a sustained, steady state release of thecorticosteroid at a rate that does not adversely suppress the HPA axis.

The corticosteroid microparticle formulation retains sustained efficacyeven after the corticosteroid is no longer resident at the site ofadministration, for example, in the intra-articular space, and/or afterthe corticosteroid is no longer detected in the systemic circulation.The corticosteroid microparticle formulation retains sustained efficacyeven after the corticosteroid microparticle formulation is no longerresident at the site of administration, for example, in theintra-articular space, and/or the corticosteroid microparticleformulation is no longer detected in the systemic circulation. Thecorticosteroid microparticle formulation retains sustained efficacy evenafter the corticosteroid microparticle formulation ceases to releasetherapeutically effective amounts of corticosteroid. For example, insome embodiments, the corticosteroid released by the microparticleformulation retains efficacy for at least one week, at least two weeks,at least three weeks, at least four weeks, at least five weeks, at leastsix weeks, at least seven weeks, at least eight weeks, at least nineweeks, at least twelve weeks, or more than twelve-weekspost-administration. In some embodiments, the corticosteroid released bythe microparticle formulation retains efficacy for a time period that isat least twice as long, at least three times as long, or more than threetimes as long as the residency period for the corticosteroid and/or thecorticosteroid microparticle formulation. In some embodiments, thesustained, steady state release of corticosteroid will not adverselysuppress the HPA axis.

In some embodiments, a controlled or sustained-release formulation isprovided wherein a microparticle matrix (such as PLGA, hydrogels,hyaluronic acid, etc.) incorporates a corticosteroid, and theformulation may or may not exhibit an initial rapid release, alsoreferred to herein as an initial “burst” of the corticosteroid for afirst length of time of between 0 and 14 days, for example, between thebeginning of day 1 through the end of day 14, in addition to thesustained, steady state release of the corticosteroid for a secondlength of time of at least two weeks, preferably at least three weeks,including up to and beyond 30 days, or 60 days, or 90 days. It should benoted that when corticosteroid levels are measured in vitro, anoccasional initial burst of corticosteroid release from themicroparticle formulation can be seen, but this initial burst may or maynot be seen in vivo. In another embodiment, a controlled orsustained-release formulation is provided wherein a microparticle matrix(such as PLGA, hydrogels, hyaluronic acid, etc.) incorporates acorticosteroid, and the formulation may or may not exhibit an initialrapid release, also referred to herein as an initial “burst” of thecorticosteroid for a first length of time of between 0 and 14 days,e.g., between the beginning of day 1 through the end of day 14, inaddition to the sustained, steady state release of the corticosteroidfor a second length of time of at least two weeks, preferably at leastthree weeks, including up to and beyond 30 days, or 60 days, or 90 dayswhere the sustained, steady state release of corticosteroid is releasedat a rate that does not suppress the HPA axis at a level greater than50% at day 14 post-administration. In some embodiments, the sustained,steady state release of corticosteroid will not adversely suppress theHPA axis, for example, the level of HPA axis suppression at or less than35% by day 14 post-administration. In some embodiments, the sustained,steady state release of corticosteroid does not significantly suppressthe HPA axis, for example, the level of HPA axis suppression isnegligible and/or undetectable by day 14 post-injection. In someembodiments, the sustained, steady state release of corticosteroid doesnot significantly suppress the HPA axis, for example, the level of HPAaxis suppression is negligible at all times post-injection. In someembodiments, the length of sustained release is between 21 days and 90days. In some embodiments, the length of sustained release is between 21days and 60 days. In some embodiments, the length of sustained releaseis between 14 days and 30 days. In some embodiments, the length ofrelease of the initial “burst” component is between 0 and 10 days, forexample between the beginning of day 1 through the end of day 10. Insome embodiments, the length of release of the initial “burst” componentis between 0 and 6 days, for example between the beginning of day 1through the end of day 6. In some embodiments, the length of initial“burst,” component is between 0 and 2 days, for example between thebeginning of day 1 through the end of day 2. In some embodiments, thelength of initial “burst” component is between 0 and 1 day, for examplebetween the beginning of day 1 through the end of day 1.

The corticosteroid microparticle formulations provided herein can beused in combination with any of a variety of therapeutics, also referredto herein as “co-therapies.” For example, the corticosteroidmicroparticle formulations can be used in combination with an immediaterelease corticosteroid solution or suspension, which provides high localexposures for between 1 day and 14 days following administration andwhich produce systemic exposures that may be associated with transientsuppression of the HPA axis. For example, 40 mg of immediate releasetriamcinolone acetonide co-administered with the corticosteroidmicroparticle formulation in the intra-articular space would be expectedto produce high local concentrations lasting for about 12 days. Thesehigh local concentrations would be associated with peak plasmaconcentration of triamcinolone acetonide of approximately 10 ng/ml onday 1, and over the course of the first 12 days of release of thetriamcinolone acetonide from the intra-articular space would beassociated with transient suppression of the HPA axis with a maximaleffect of approximately 60% suppression of cortisol on day 1-2(Derendorf et al., “Pharmacokinetics and pharmacodynamics ofglucocorticoid suspensions after intra-articular administration.” ClinPharmacol Ther. 39(3) (1986):313-7). By day 12, the contribution of theimmediate release component to the plasma concentration would be small,less than 0.1 ng/ml, and the contribution to the intra articularconcentration of the immediate release component would also be small.However at day 12 and beyond, the corticosteroid microparticleformulation would continue to release corticosteroid in the intraarticular space at a rate that extends the duration of therapeuticeffect and does not suppress the HPA axis. In some embodiments, the samecorticosteroid is used in both the immediate release and sustainedrelease components. In some embodiments, the immediate release componentcontains a corticosteroid that is different from that of the sustainedrelease component. In some embodiments, the sustained, steady staterelease of corticosteroid will not adversely suppress the HPA axis. Insome embodiments, the period of sustained release is between 21 days and90 days. In some embodiments, the period of sustained release is between21 days and 60 days. In some embodiments, the period of sustainedrelease is between 14 days and 30 days. In some embodiments, the highlocal exposure attributable to the immediate release component lasts forbetween 1 day and 14 days. In some embodiments, the high local exposureattributable to the immediate release component lasts for between 1 dayand 10 days. In some embodiments, the high local exposure attributableto the immediate release component lasts between 1 days and 8 days. Insome embodiments, the high local exposure attributable to the immediaterelease component lasts between 1 days and 6 days. In some embodiments,the high local exposure attributable to the immediate release componentlasts for between 1 day and 4 days.

Upon administration, the corticosteroid microparticle formulation mayprovide an initial release of corticosteroid at the site ofadministration, for example, in the intra-articular space and/orperi-articular space. Once the initial release of corticosteroid hassubsided, the controlled or sustained release of the corticosteroidmicroparticle formulations continues to provide therapeutic (e.g.,intra-articular and/or peri-articular) concentrations of corticosteroidto suppress inflammation, maintain analgesia, and/or slow, arrest orreverse structural damage to tissues for an additional period of therapyfollowing administration (FIG. 1, top tracings). However, the systemicexposure associated with the sustained release component does notsuppress the HPA axis (FIG. 1, bottom tracings). Thus, the inventionincludes therapies and formulations that may exhibit an initial releaseof corticosteroid followed by controlled or sustained release where thetherapy comprises a period of therapy wherein the corticosteroid isreleased from the sustained release component and the plasma levels ofthe corticosteroid does not adversely suppress the HPA axis.

In some embodiments, the length of sustained release is between 21 daysand 90 days. In some embodiments, the length of sustained release isbetween 21 days and 60 days. In some embodiments, the length ofsustained release is between 14 days and 30 days. In some embodiments,the length of release of the immediate release form is between 1 day and14 days. In some embodiments, the length of release of the immediaterelease form is between 1 day and 10 days. In some embodiments, thelength of release of the immediate release form is between 1 day and 8days. In some embodiments, the length of release of the immediaterelease form is between 1 day and 6 days. In some embodiments, thelength of release of the immediate release form is between 1 day and 4days.

The invention provides populations of microparticles including a Class Bcorticosteroid or a pharmaceutically acceptable salt thereofincorporated in, admixed, encapsulated or otherwise associated with alactic acid-glycolic acid copolymer matrix, wherein the Class Bcorticosteroid is between 22% to 28% of the microparticles.

The invention also provides controlled or sustained release preparationof a Class B corticosteroid that include a lactic acid-glycolic acidcopolymer microparticle containing the Class B corticosteroid, whereinthe Class B corticosteroid is between 22% to 28% of the lacticacid-glycolic acid copolymer microparticle matrix.

The invention also provides formulations that include (a) controlled- orsustained-release microparticles comprising a Class B corticosteroid anda lactic acid-glycolic acid copolymer matrix, wherein the Class Bcorticosteroid comprises between 22% to 28% of the microparticles andwherein the lactic acid-glycolic acid copolymer has one of more of thefollowing characteristics: (i) a molecular weight in the range of about40 to 70 kDa; (ii) an inherent viscosity in the range of 0.3 to 0.5dL/g; (iii) a lactide:glycolide molar ratio of 80:20 to 60:40; and/or(iv) the lactic acid-glycolic acid copolymer is carboxylic acidendcapped.

In some embodiments of these populations, preparations and/orformulations, the copolymer is biodegradable. In some embodiments, thelactic acid-glycolic acid copolymer is a poly(lactic-co-glycolic) acidcopolymer (PLGA). In some embodiments, the lactic acid-glycolic acidcopolymer has a molar ratio of lactic acid: glycolic acid from the rangeof about 80:20 to 60:40. In some embodiments, the lactic acid-glycolicacid copolymer has a molar ratio of lactic acid: glycolic acid of 75:25.

The invention also provides populations of microparticles including aClass B corticosteroid or a pharmaceutically acceptable salt thereofincorporated in, admixed, encapsulated or otherwise associated with amixed molecular weight lactic acid-glycolic acid copolymer matrix,wherein the Class B corticosteroid is between 12% to 28% of themicroparticles. In some embodiments, the corticosteroid microparticleformulation includes a Class B corticosteroid and a microparticle madeusing 75:25 PLGA formulation with two PLGA polymers, one of lowmolecular weight and one of high molecular weight in a two to one ratio,respectively. The low molecular weight PLGA has a molecular weight ofrange of 15-35 kDa and an inherent viscosity range from 0.2 to 0.35 dL/gand the high molecular weight PLGA has a range of 70-95 kDa and aninherent viscosity range of 0.5 to 0.70 dL/g. In these TCA/75:25 PLGAcorticosteroid microparticle formulations, the microparticles have amean diameter in the range of 10-100 μM. In some embodiments, themicroparticles have a mean diameter in the range of 20-100 μM, 20-90 μM,30-100 μM, 30-90 μM, or 10-90 μM. It is understood that these rangesrefer to the mean diameter of all microparticles in a given population.The diameter of any given individual microparticle could be within astandard deviation above or below the mean diameter.

The invention also provides populations of microparticles including aClass B corticosteroid or a pharmaceutically acceptable salt thereofincorporated in, admixed, encapsulated or otherwise associated with alactic acid-glycolic acid copolymer matrix containing 10-20% triblock(PEG—PLGA-PEG) having an inherent viscosity in the range from 0.6 to 0.8dL/g, wherein the Class B corticosteroid is between 22% to 28% of themicroparticles. In some embodiments, the corticosteroid microparticleformulation includes a Class B corticosteroid and a microparticle madeusing 75:25 PLGA formulation and containing 10-20% triblock(PEG—PLGA-PEG) having an inherent viscosity in the range from 0.6 to 0.8dL/g. In these TCA/75:25 PLGA corticosteroid microparticle formulations,the microparticles have a mean diameter in the range of 10-100 μM. Insome embodiments, the microparticles have a mean diameter in the rangeof 20-100 M, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM. It isunderstood that these ranges refer to the mean diameter of allmicroparticles in a given population. The diameter of any givenindividual microparticle could be within a standard deviation above orbelow the mean diameter.

These Class B corticosteroid microparticle formulations, preparations,and populations thereof, when administered to a patient, exhibit reducedundesirable side effects in patient, for example, undesirable effects ona patient's cartilage or other structural tissue, as compared to theadministration, for example administration into the intra-articularspace of a joint, of an equivalent amount of the Class B corticosteroidabsent any microparticle or other type of incorporation, admixture, orencapsulation.

In some embodiments, the Class B corticosteroid is triamcinoloneacetonide or a commercially available chemical analogue or apharmaceutically-acceptable salt thereof. In some embodiments, the totaldose of corticosteroid contained in the microparticles is in the rangeof 10-90 mg, where the Class B corticosteroid is between 12-28% of themicroparticle, for example, between 22-28% of the microparticle (i.e.,when the corticosteroid is 28% of the microparticle, the microparticleis in the range of 35.7-321.4 mgs, and so on for all values between22-28% load dose, when the corticosteroid is 25% of the microparticle,the microparticle is in the range of 40-360 mgs, when the corticosteroidis 22% of the microparticle, the microparticle is in the range of45.5-409.1 mgs, when the corticosteroid is 12% of the microparticle, themicroparticle is in the range of 83.3-750 mgs, and so on for all valuesbetween 12-28% load dose). In some embodiments, the Class Bcorticosteroid contained in the microparticles is 12-28% of themicroparticle, for example, between 22-28% of the microparticle and thetotal dose of corticosteroid is in a range selected from 10-80 mg, 10-70mg, 10-60 mg, 10-50 mg, 10-40 mg, 10-30 mg, 10-20 mg, 20-90 mg, 20-80mg, 20-70 mg, 20-60 mg, 20-50 mg, 20-40 mg, 20-30 mg, 30-90 mg, 30-80mg, 30-70 mg, 30-60 mg, 30-50 mg, 30-40 mg, 40-90 mg, 40-80 mg, 40-70mg, 40-60 mg, 40-50 mg, 50-90 mg, 50-80 mg, 50-70 mg, 50-60 mg, 60-90mg, 60-80 mg, 60-70 mg, 70-90 mg, 70-80 mg, and 80-90 mg. In someembodiments, the Class B corticosteroid is released for between 14 daysand 90 days.

In some embodiments, the microparticles have a mean diameter of between10 μm to 100 μm, for example, the microparticles have a mean diameter inthe range of 20-100 μM, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM. Itis understood that these ranges refer to the mean diameter of allmicroparticles in a given population. The diameter of any givenindividual microparticle could be within a standard deviation above orbelow the mean diameter.

In some embodiments, the microparticles further comprise a polyethyleneglycol (PEG) moiety, wherein the PEG moiety comprises between 25% to 0%weight percent of the microparticle. In some embodiments of themicroparticles that include a PEG moiety, the populations, preparationsand/or formulations of the invention do not require the presence of PEGto exhibit the desired corticosteroid sustained release kinetics andbioavailability profile.

In one embodiment of these populations, preparations and/orformulations, the corticosteroid microparticle formulation includestriamcinolone acetonide (TCA) and a microparticle made using 75:25 PLGAformulation having an inherent viscosity in the range from 0.3 to 0.5dL/g and/or a molecular weight in the range of 40-70 kDa, for examplebetween 50-60 kDa. In these TCA/75:25 PLGA corticosteroid microparticleformulations, the microparticles have a mean diameter in the range of10-100 μM. In some embodiments, the microparticles have a mean diameterin the range of 20-100 μM, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM.It is understood that these ranges refer to the mean diameter of allmicroparticles in a given population. The diameter of any givenindividual microparticle could be within a standard deviation above orbelow the mean diameter.

For the TCA/75:25 PLGA microparticle formulations, the range of TCA loadpercentage is between 22-28%. In one embodiment, the load percentage ofTCA in the microparticles in 25%.

The microparticles in the TCA PLGA microparticle formulations can beformulated using PLGA polymers having a range of molecular weights from40 to 70 kDa, most preferably from 50 to 60 kDa and range of inherentviscosities from 0.5 to 0.5 dL/g, most preferably from 0.38 to 0.42dL/g.

For the TCA/75:25 PLGA microparticle formulations, the total dose ofcorticosteroid contained in the microparticles is in the range of 10-90mg, where TCA is between 22-28% of the microparticle (i.e., when TCA is25% of the microparticle, the microparticle is in the range of 40-360mgs, when TCA is 22% of the microparticle, the microparticle is in therange of 45.5-409.1 mgs, when TCA is 28% of the microparticle, themicroparticle is in the range of 35.7-321.4 mgs, and so on for allvalues between 22-28% load dose). In some embodiments, total dose ofcorticosteroid contained in the microparticles is in a range selectedfrom 10-80 mg, 10-70 mg, 10-60 mg, 10-50 mg, 10-40 mg, 10-30 mg, 10-20mg, 20-90 mg, 20-80 mg, 20-70 mg, 20-60 mg, 20-50 mg, 20-40 mg, 20-30mg, 30-90 mg, 30-80 mg, 30-70 mg, 30-60 mg, 30-50 mg, 30-40 mg, 40-90mg, 40-80 mg, 40-70 mg, 40-60 mg, 40-50 mg, 50-90 mg, 50-80 mg, 50-70mg, 50-60 mg, 60-90 mg, 60-80 mg, 60-70 mg, 70-90 mg, 70-80 mg, and80-90mg.

In some embodiments of the TCA/75:25 PLGA microparticle formulations,the microparticles further comprise a polyethylene glycol (PEG) moiety,wherein the PEG moiety comprises between 25% to 0% weight percent of themicroparticle. In some embodiments of the microparticles that include aPEG moiety, the populations, preparations and/or formulations of theinvention do not require the presence of PEG to exhibit the desiredcorticosteroid sustained release kinetics and bioavailability profile.

In one embodiment of these populations, preparations and/orformulations, the corticosteroid microparticle formulation includestriamcinolone acetonide (TCA) and a microparticle made using 75:25 PLGAformulation and containing 10-20% triblock (PEG-PLGA-PEG) having aninherent viscosity in the range from 0.6 to 0.8 dL/g. In these TCA/75:25PLGA corticosteroid microparticle formulations, the microparticles havea mean diameter in the range of 10-100 μM. In some embodiments, themicroparticles have a mean diameter in the range of 20-100 μM, 20-90 μM,30-100 μM, 30-90 μM, or 10-90 μM. It is understood that these rangesrefer to the mean diameter of all microparticles in a given population.The diameter of any given individual microparticle could be within astandard deviation above or below the mean diameter.

In one embodiment of these populations, preparations and/orformulations, the corticosteroid microparticle formulation includestriamcinolone acetonide (TCA) and a microparticle made using 75:25 PLGAformulation with two PLGA polymers, one of low molecular weight and oneof high molecular weight in a two to one ratio, respectively. The lowmolecular weight PLGA has a molecular weight of range of 15-35 kDa andan inherent viscosity range from 0.2 to 0.35 dL/g and the high molecularweight PLGA has a range of 70-95 kDa and an inherent viscosity range of0.5 to 0.70 dL/g. In these TCA/75:25 PLGA corticosteroid microparticleformulations, the microparticles have a mean diameter in the range of10-100 μM. In some embodiments, the microparticles have a mean diameterin the range of 20-100 μM, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM.It is understood that these ranges refer to the mean diameter of allmicroparticles in a given population. The diameter of any givenindividual microparticle could be within a standard deviation above orbelow the mean diameter.

These TCA microparticle formulations, preparations, and populationsthereof, when administered to a patient, exhibit reduced undesirableside effects in patient, for example, undesirable effects on a patient'scartilage or other structural tissue, as compared to the administration,for example administration into the intra-articular space of a joint, ofan equivalent amount of TCA absent any microparticle or other type ofincorporation, admixture, or encapsulation.

In another embodiment, the corticosteroid microparticle formulationincludes a Class A, C, or D corticosteroid and a microparticle madeusing 50:50 PLGA formulation. For example, in some embodiments, theClass A corticosteroid is prednisolone. In some embodiments, the Class Ccorticosteroid is betamethasone. In some embodiments, the Class Dcorticosteroid is fluticasone or fluticasone propionate. In these ClassA, C, or D corticosteroid microparticle formulations, the microparticleshave a mean diameter in the range of 10-100 μM. In some embodiments, themicroparticles have a mean diameter in the range of 20-100 μM, 20-90 μM,30-100 μM, 30-90 μM, or 10-90 μM. It is understood that these rangesrefer to the mean diameter of all microparticles in a given population.The diameter of any given individual microparticle could be within astandard deviation above or below the mean diameter.

For the Class A and/or Class C PLGA microparticle formulations, therange of corticosteroid load percentage is between 10-40%, for example,between 15%-30%. For the Class D PLGA microparticle formulations, therange of corticosteroid load percentage is between 8-20%.

The microparticles in the Class A, C or D PLGA microparticleformulations can be formulated using PLGA polymers having a range ofinherent viscosities from 0.35 to 0.5 dL/g and approximated molecularweights from 40 kDa to 70 kDa.

These Class A, C or D corticosteroid microparticle formulations,preparations, and populations thereof, when administered to a patient,exhibit reduced undesirable side effects in patient, for example,undesirable effects on a patient's cartilage or other structural tissue,as compared to the administration, for example administration into theintra-articular space of a joint, of an equivalent amount of the ClassA, C or D corticosteroid absent any microparticle or other type ofincorporation, admixture, or encapsulation.

The invention provides populations of microparticles including a Class Acorticosteroid or a pharmaceutically acceptable salt thereofincorporated in, admixed, encapsulated or otherwise associated with alactic acid-glycolic acid copolymer matrix, wherein the Class Acorticosteroid is between 15% to 30% of the microparticles.

The invention also provides controlled or sustained release preparationsof a Class A corticosteroid including a lactic acid-glycolic acidcopolymer microparticle containing the Class A corticosteroid, whereinthe Class A corticosteroid is between 10% to 40%, for example between15% to 30% of the lactic acid-glycolic acid copolymer microparticlematrix.

The invention provides formulations that include (a) controlled- orsustained-release microparticles including a Class A corticosteroid anda lactic acid-glycolic acid copolymer matrix, wherein the Class Acorticosteroid is between 15% to 30% of the microparticles and whereinthe lactic acid-glycolic acid copolymer has one of more of the followingcharacteristics: (i) a molecular weight in the range of about 40 to 70kDa; (ii) an inherent viscosity in the range of 0.35 to 0.5 dL/g; (iii)a lactide:glycolide molar ratio of 60:40 to 45:55; and/or (iv) thelactic acid-glycolic acid copolymer is carboxylic acid endcapped

In some embodiments, the copolymer is biodegradable. In someembodiments, the lactic acid-glycolic acid copolymer is apoly(lactic-co-glycolic) acid copolymer (PLGA). In some embodiments, thelactic acid-glycolic acid copolymer has a molar ratio of lactic acid:glycolic acid from the range of about 60:40 to 45:55. In someembodiments, the lactic acid-glycolic acid copolymer has a molar ratioof lactic acid: glycolic acid of 50:50.

In some embodiments, the Class A corticosteroid is prednisolone or acommercially available chemical analogue or apharmaceutically-acceptable salt thereof. In some embodiments, totaldose of the Class A corticosteroid contained in the microparticles is ina range selected from 10-250 mg, where the Class A corticosteroid isbetween 10-40%, for example, between 15-30% of the microparticle (i.e.,when the corticosteroid is 10% of the microparticle, the microparticleis in the range of 100-2500 mgs, when the corticosteroid is 15% of themicroparticle, the microparticle is in the range of 66.7-1666.7 mgs,when the corticosteroid is 20% of the microparticle, the microparticleis in the range of 50-1250 mgs, when the corticosteroid is 25% of themicroparticle, the microparticle is in the range of 40-1000 mgs, whenthe corticosteroid is 30% of the microparticle, the microparticle is inthe range of 33.3-833.3 mgs, when the corticosteroid is 40% of themicroparticle, the microparticle is in the range of 25-625 mgs and so onfor all values between 10-40% load dose). For example, in someembodiments, the total dose of corticosteroid is in the range of 10-225mg, 10-200 mg, 10-175 mg, 10-150 mg, 10-120 mg, 10-100 mg, 10-75 mg,10-50 mg, 10-25 mg, 20-250 mg, 20-225 mg, 20-200 mg, 20-175 mg, 20-150mg, 20-125 mg, 20-100 mg, 20-75 mg, 20-50 mg, 30-250 mg, 30-225 mg,30-200 mg, 30-175 mg, 30-150 mg, 30-120 mg, 30-100 mg, 30-75 mg, 30-50mg, 40-250 mg, 40-225 mg, 40-200 mg, 40-175 mg, 40-150 mg, 40-120 mg,40-100 mg, 40-75 mg, 50-250 mg, 50-225 mg, 50-200 mg, 50-175 mg, 50-150mg, 50-120 mg, 50-100 mg, 50-75 mg, 60-250 mg, 60-225 mg, 60-200 mg,60-175 mg, 60-150 mg, 60-120 mg, 60-100 mg, 60-75 mg, 70-250 mg, 70-225mg, 70-200 mg, 70-175 mg, 70-150 mg, 70-120 mg, 70-100 mg, 80-250 mg,80-225 mg, 80-200 mg, 80-175 mg, 80-150 mg, 80-120 mg, 80-100 mg, 90-250mg, 90-225 mg, 90-200 mg, 90-175 mg, 90-150 mg, or 90-120 mg. In someembodiments, the Class A corticosteroid is released for between 14 daysand 90 days.

In some embodiments, the microparticles have a mean diameter of between10 μm to 100 μm, for example, the microparticles have a mean diameter inthe range of 20-100 μM, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM. Itis understood that these ranges refer to the mean diameter of allmicroparticles in a given population. The diameter of any givenindividual microparticle could be within a standard deviation above orbelow the mean diameter.

In some embodiments, the microparticles further comprise a polyethyleneglycol (PEG) moiety, wherein the PEG moiety comprises between 25% to 0%weight percent of the microparticle. In some embodiments of themicroparticles that include a PEG moiety, the populations, preparationsand/or formulations of the invention do not require the presence of PEGto exhibit the desired corticosteroid sustained release kinetics andbioavailability profile.

In one embodiment of these populations, preparations and/orformulations, the corticosteroid microparticle formulation includesprednisolone and a microparticle made using 50:50 PLGA formulationhaving a molecular weight in the range of 40 kDa to 70 kDa. In theseprednisolone/50:50 PLGA corticosteroid microparticle formulations, themicroparticles have a mean diameter in the range of 10-100 μM. In someembodiments, the microparticles have a mean diameter in the range of20-100 μM, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM.

For the prednisolone/50:50 PLGA microparticle formulations, the range ofprednisolone load percentage is between 10-40%, for example, between15-30%.

In some embodiments of the prednisolone/50:50 PLGA microparticleformulations, the microparticles further comprise a polyethylene glycol(PEG) moiety, wherein the PEG moiety comprises between 25% to 0% weightpercent of the microparticle. In some embodiments of the microparticlesthat include a PEG moiety, the populations, preparations and/orformulations of the invention do not require the presence of PEG toexhibit the desired corticosteroid sustained release kinetics andbioavailability profile.

The invention provides populations of microparticles including a Class Ccorticosteroid or a pharmaceutically acceptable salt thereofincorporated in, admixed, encapsulated or otherwise associated with alactic acid-glycolic acid copolymer matrix, wherein the Class Ccorticosteroid is between 10% to 40% of the microparticles, for examplebetween 15% to 30% of the microparticles.

The invention also provides controlled or sustained release preparationsof a Class C corticosteroid including a lactic acid-glycolic acidcopolymer microparticle containing the Class C corticosteroid, whereinthe Class C corticosteroid is between 15% to 30% of the lacticacid-glycolic acid copolymer microparticle matrix.

The invention provides formulations that include (a) controlled- orsustained-release microparticles having a Class C corticosteroid and alactic acid-glycolic acid copolymer matrix, wherein the Class Ccorticosteroid is between 15% to 30% of the microparticles and whereinthe lactic acid-glycolic acid copolymer has one of more of the followingcharacteristics: (i) a molecular weight in the range of about 40 to 70kDa; (ii) an inherent viscosity in the range of 0.35 to 0.5 dL/g; (iii)a lactide:glycolide molar ratio of 60:40 to 45:55; and/or (iv) thelactic acid-glycolic acid copolymer is carboxylic acid endcapped.

In one embodiment of these populations, preparations and/orformulations, the copolymer is biodegradable. In some embodiments, thelactic acid-glycolic acid copolymer is a poly(lactic-co-glycolic) acidcopolymer (PLGA). In some embodiments, the lactic acid-glycolic acidcopolymer has a molar ratio of lactic acid: glycolic acid from the rangeof about 60:40 to 45:55. In some embodiments, the lactic acid-glycolicacid copolymer has a molar ratio of lactic acid: glycolic acid of 50:50.

In some embodiments, the Class C corticosteroid is betamethasone or acommercially available chemical analogue or apharmaceutically-acceptable salt thereof. In some embodiments, totaldose of the Class C corticosteroid contained in the microparticles is ina range selected from 2-250 mg, where the Class C corticosteroid isbetween 10-40%, for example, between 15-30% of the microparticle (i.e.,when the corticosteroid is 10% of the microparticle, the microparticleis in the range of 20-2500 mgs, when the corticosteroid is 15% of themicroparticle, the microparticle is in the range of 13.3-1666.7 mgs,when the corticosteroid is 20% of the microparticle, the microparticleis in the range of 10-1250 mgs, when the corticosteroid is 25% of themicroparticle, the microparticle is in the range of 8-1000 mgs, when thecorticosteroid is 30% of the microparticle, the microparticle is in therange of 6.67-833.3 mgs, when the corticosteroid is 40% of themicroparticle, the microparticle is in the range of 5-625 mgs and so onfor all values between 10-40% load dose). For example, in someembodiments, the total dose of corticosteroid is in the range of 2-225mg, 2-200 mg, 2-175 mg, 2-150 mg, 2-120 mg, 2-100 mg, 2-75 mg, 2-60 mg,2-55 mg, 2-50 mg, 2-45 mg, 2-40 mg, 2-35 mg, 2-30 mg, 2-25 mg, 2-20 mg,2-15 mg, 2-10 mg, 4-225 mg, 4-200 mg, 4-175 mg, 4-150 mg, 4-120 mg,4-100 mg, 4-75 mg, 4-60 mg, 4-55 mg, 4-50 mg, 4-45 mg, 4-40 mg, 4-35 mg,4-30 mg, 4-25 mg, 4-20 mg, 4-15 mg, 4-10 mg, 5-225 mg, 5-200 mg, 5-175mg, 5-150 mg, 5-120 mg, 5-100 mg, 5-75 mg, 5-60 mg, 5-55 mg, 5-50 mg,5-45 mg, 5-40 mg, 5-35 mg, 5-30 mg, 5-25 mg, 5-20 mg, 5-15 mg, 5-10 mg,6-225 mg, 6-200 mg, 6-175 mg, 6-150 mg, 6-120 mg, 6-100 mg, 6-75 mg,6-60 mg, 6-55 mg, 6-50 mg, 6-45 mg, 6-40 mg, 6-35 mg, 6-30 mg, 6-25 mg,6-20 mg, 6-15 mg, 6-10 mg, 8-225 mg, 8-200 mg, 8-175 mg, 8-150 mg, 8-120mg, 8-100 mg, 8-75 mg, 8-60 mg, 8-55 mg, 8-50 mg, 8-45 mg, 8-40 mg, 8-35mg, 8-30 mg, 8-25 mg, 8-20 mg, 8-15 mg, 8-10 mg, 10-225 mg, 10-200 mg,10-175 mg, 10-150 mg, 10-120 mg, 10-100 mg, 10-75 mg, 10-50 mg, 10-25mg, 20-250 mg, 20-225 mg, 20-200 mg, 20-175 mg, 20-150 mg, 20-125 mg,20-100 mg, 20-75 mg, 20-50 mg, 30-250 mg, 30-225 mg, 30-200 mg, 30-175mg, 30-150 mg, 30-120 mg, 30-100 mg, 30-75 mg, 30-50 mg, 40-250 mg,40-225 mg, 40-200 mg, 40-175 mg, 40-150 mg, 40-120 mg, 40-100 mg, 40-75mg, 50-250 mg, 50-225 mg, 50-200 mg, 50-175 mg, 50-150 mg, 50-120 mg,50-100 mg, 50-75 mg, 60-250 mg, 60-225 mg, 60-200 mg, 60-175 mg, 60-150mg, 60-120 mg, 60-100 mg, 60-75 mg, 70-250 mg, 70-225 mg, 70-200 mg,70-175 mg, 70-150 mg, 70-120 mg, 70-100 mg, 80-250 mg, 80-225 mg, 80-200mg, 80-175 mg, 80-150 mg, 80-120 mg, 80-100 mg, 90-250 mg, 90-225 mg,90-200 mg, 90-175 mg, 90-150 mg, or 90-120 mg. In some embodiments, theClass C corticosteroid is released for between 14 days and 90 days.

In some embodiments, the microparticles have a mean diameter of between10 μm to 100 μm, for example, the microparticles have a mean diameter inthe range of 20-100 μM, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM. Itis understood that these ranges refer to the mean diameter of allmicroparticles in a given population. The diameter of any givenindividual microparticle could be within a standard deviation above orbelow the mean diameter.

In some embodiments, the microparticles further comprise a polyethyleneglycol (PEG) moiety, wherein the PEG moiety comprises between 25% to 0%weight percent of the microparticle. In some embodiments of themicroparticles that include a PEG moiety, the populations, preparationsand/or formulations of the invention do not require the presence of PEGto exhibit the desired corticosteroid sustained release kinetics andbioavailability profile.

In one embodiment of these populations, preparations and/orformulations, the corticosteroid microparticle formulation includesbetamethasone and a microparticle made using 50:50 PLGA formulationhaving a molecular weight in the range of 40 kDa to 70 kDa. In thesebetamethasone/50:50 PLGA corticosteroid microparticle formulations, themicroparticles have a mean diameter in the range of 10-100 μM. In someembodiments, the microparticles have a mean diameter in the range of20-100 μM, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM. It is understoodthat these ranges refer to the mean diameter of all microparticles in agiven population. The diameter of any given individual microparticlecould be within a standard deviation above or below the mean diameter.

For the betamethasone/50:50 PLGA microparticle formulations, the rangeof prednisolone load percentage is between 10-40%, for example, between15-30%.

In some embodiments of the betamethasone/50:50 PLGA microparticleformulations, the microparticles further comprise a polyethylene glycol(PEG) moiety, wherein the PEG moiety comprises between 25% to 0% weightpercent of the microparticle. In some embodiments of the microparticlesthat include a PEG moiety, the populations, preparations and/orformulations of the invention do not require the presence of PEG toexhibit the desired corticosteroid sustained release kinetics andbioavailability profile.

The invention provides populations of microparticles including a Class Dcorticosteroid or a pharmaceutically acceptable salt thereofincorporated in, admixed, encapsulated or otherwise associated with alactic acid-glycolic acid copolymer matrix, wherein the Class Dcorticosteroid is between 8% to 20% of the microparticles, for example,between 10% to 20% of the microparticles.

The invention also provides controlled or sustained release preparationof a Class D corticosteroid including a lactic acid-glycolic acidcopolymer microparticle containing the Class D corticosteroid, whereinthe Class D corticosteroid is between 8% to 20%, for example, between10% to 20% of the microparticles of the lactic acid-glycolic acidcopolymer microparticle matrix.

The invention provides formulations including (a) controlled- orsustained-release microparticles having a Class D corticosteroid and alactic acid-glycolic acid copolymer matrix, wherein the Class Dcorticosteroid is between 8% to 20% of the microparticles, for example,between 10% to 20% of the microparticles, and wherein the lacticacid-glycolic acid copolymer has one of more of the followingcharacteristics: (i) a molecular weight in the range of about 40 to 70kDa; (ii) an inherent viscosity in the range of 0.35 to 0.5 dL/g; (iii)a lactide:glycolide molar ratio of 60:40 to 45:55; and/or (iv) thelactic acid-glycolic acid copolymer is carboxylic acid endcapped.

In one embodiment of these populations, preparations and/orformulations, the copolymer is biodegradable. In some embodiments, thelactic acid-glycolic acid copolymer is a poly(lactic-co-glycolic) acidcopolymer (PLGA). In some embodiments, the lactic acid-glycolic acidcopolymer has a molar ratio of lactic acid: glycolic acid from the rangeof about 60:40 to 45:55. In some embodiments, the lactic acid-glycolicacid copolymer has a molar ratio of lactic acid: glycolic acid of 50:50.

In some embodiments, the Class D corticosteroid is fluticasonepropionate, fluticasone, or a commercially available chemical analogueor a pharmaceutically-acceptable salt thereof. In some embodiments,total dose of the Class D corticosteroid contained in the microparticlesis in a range selected from 1-250 mg, where the Class D corticosteroidis between 8-20% of the microparticle (i.e., when the corticosteroid is8% of the microparticle, the microparticle is in the range of 12.5-3125mgs, when the corticosteroid is 10% of the microparticle, themicroparticle is in the range of 10-2500 mgs, when the corticosteroid is15% of the microparticle, the microparticle is in the range of6.67-1666.7 mgs, when the corticosteroid is 20% of the microparticle,the microparticle is in the range of 5-1250 mgs, and so on for allvalues between 10-20% load dose). For example, in some embodiments, thetotal dose of corticosteroid is in the range of 1-225 mg, 1-200 mg,1-175 mg, 1-150 mg, 1-120 mg, 1-100 mg, 1-75 mg, 1-60 mg, 1-55 mg, 1-50mg, 1-45 mg, 1-40 mg, 1-35 mg, 1-30 mg, 1-25 mg, 1-20 mg, 1-15 mg, 1-10mg, 2-225 mg, 2-200 mg, 2-175 mg, 2-150 mg, 2-120 mg, 2-100 mg, 2-75 mg,2-60 mg, 2-55 mg, 2-50 mg, 2-45 mg, 2-40 mg, 2-35 mg, 2-30 mg, 2-25 mg,2-20 mg, 2-15 mg, 2-10 mg, 3-225 mg, 3-200 mg, 3-175 mg, 3-150 mg, 3-120mg, 3-100 mg, 3-75 mg, 3-60 mg, 3-55 mg, 3-50 mg, 3-45 mg, 3-40 mg, 3-35mg, 3-30 mg, 3-25 mg, 3-20 mg, 3-15 mg, 3-10 mg, 4-225 mg, 4-200 mg,4-175 mg, 4-150 mg, 4-120 mg, 4-100 mg, 4-75 mg, 4-60 mg, 4-55 mg, 4-50mg, 4-45 mg, 4-40 mg, 4-35 mg, 4-30 mg, 4-25 mg, 4-20 mg, 4-15 mg, 4-10mg, 5-225 mg, 5-200 mg, 5-175 mg, 5-150 mg, 5-120 mg, 5-100 mg, 5-75 mg,5-60 mg, 5-55 mg, 5-50 mg, 5-45 mg, 5-40 mg, 5-35 mg, 5-30 mg, 5-25 mg,5-20 mg, 5-15 mg, 5-10 mg, 6-225 mg, 6-200 mg, 6-175 mg, 6-150 mg, 6-120mg, 6-100 mg, 6-75 mg, 6-60 mg, 6-55 mg, 6-50 mg, 6-45 mg, 6-40 mg, 6-35mg, 6-30 mg, 6-25 mg, 6-20 mg, 6-15 mg, 6-10 mg, 8-225 mg, 8-200 mg,8-175 mg, 8-150 mg, 8-120 mg, 8-100 mg, 8-75 mg, 8-60 mg, 8-55 mg, 8-50mg, 8-45 mg, 8-40 mg, 8-35 mg, 8-30 mg, 8-25 mg, 8-20 mg, 8-15 mg, 8-10mg, 10-225 mg, 10-200 mg, 10-175 mg, 10-150 mg, 10-120 mg, 10-100 mg,10-75 mg, 10-50 mg, 10-25 mg, 20-250 mg, 20-225 mg, 20-200 mg, 20-175mg, 20-150 mg, 20-125 mg, 20-100 mg, 20-75 mg, 20-50 mg, 30-250 mg,30-225 mg, 30-200 mg, 30-175 mg, 30-150 mg, 30-120 mg, 30-100 mg, 30-75mg, 30-50 mg, 40-250 mg, 40-225 mg, 40-200 mg, 40-175 mg, 40-150 mg,40-120 mg, 40-100 mg, 40-75 mg, 50-250 mg, 50-225 mg, 50-200 mg, 50-175mg, 50-150 mg, 50-120 mg, 50-100 mg, 50-75 mg, 60-250 mg, 60-225 mg,60-200 mg, 60-175 mg, 60-150 mg, 60-120 mg, 60-100 mg, 60-75 mg, 70-250mg, 70-225 mg, 70-200 mg, 70-175 mg, 70-150 mg, 70-120 mg, 70-100 mg,80-250 mg, 80-225 mg, 80-200 mg, 80-175 mg, 80-150 mg, 80-120 mg, 80-100mg, 90-250 mg, 90-225 mg, 90-200 mg, 90-175 mg, 90-150 mg, or 90-120 mg.In some embodiments, the Class D corticosteroid is released for between14 days and 90 days.

In some embodiments, the microparticles have a mean diameter of between10 μm to 100 μm, for example, the microparticles have a mean diameter inthe range of 20-100 μM, 20-90 μM, 30-100 μM, 30-90 μM, or 10-90 μM. Itis understood that these ranges refer to the mean diameter of allmicroparticles in a given population. The diameter of any givenindividual microparticle could be within a standard deviation above orbelow the mean diameter.

In some embodiments, the microparticles further comprise a polyethyleneglycol (PEG) moiety, wherein the PEG moiety comprises between 25% to 0%weight percent of the microparticle. In some embodiments of themicroparticles that include a PEG moiety, the populations, preparationsand/or formulations of the invention do not require the presence of PEGto exhibit the desired corticosteroid sustained release kinetics andbioavailability profile.

In one embodiment of these populations, preparations and/orformulations, the corticosteroid microparticle formulation includesfluticasone propionate or fluticasone, and a microparticle made using50:50 PLGA formulation having a molecular weight in the range of 40 kDato 70 kDa. In these fluticasone or fluticasone propionate/50:50 PLGAcorticosteroid microparticle formulations, the microparticles have amean diameter in the range of 10-100 μM. In some embodiments, themicroparticles have a mean diameter in the range of 20-100 μM, 20-90 μM,30-100 μM, 30-90 μM, or 10-90 μM. It is understood that these rangesrefer to the mean diameter of all microparticles in a given population.The diameter of any given individual microparticle could be within astandard deviation above or below the mean diameter.

For the fluticasone or fluticasone propionate/50:50 PLGA microparticleformulations, the range of prednisolone load percentage is between10-20%.

In some embodiments of the fluticasone or fluticasone propionate/50:50PLGA microparticle formulations, the microparticles further comprise apolyethylene glycol (PEG) moiety, wherein the PEG moiety comprisesbetween 25% to 0% weight percent of the microparticle. In someembodiments of the microparticles that include a PEG moiety, thepopulations, preparations and/or formulations of the invention do notrequire the presence of PEG to exhibit the desired corticosteroidsustained release kinetics and bioavailability profile.

These embodiments of corticosteroid microparticle formulations have beenselected because the combination of class of corticosteroid, type ofmicroparticle, molecular weight of polymers used to create themicroparticles lactide:glycolide molar ratio, and/or load percentage ofthe corticosteroid exhibit the desired release kinetics. Theseembodiments also exhibit the desired release kinetics with minimalprolonged HPA axis suppression.

The invention provides methods of treating pain or inflammation in apatient comprising administering to said patient a therapeuticallyeffective amount of a population of microparticles selected from thefollowing populations: (i) a population of microparticles comprising aClass B corticosteroid or a pharmaceutically acceptable salt thereofincorporated in a lactic acid-glycolic acid copolymer matrix, whereinthe Class B corticosteroid comprises between 22% to 28% of themicroparticles; (ii) a population of microparticles comprising a Class Acorticosteroid or a pharmaceutically acceptable salt thereofincorporated in a lactic acid-glycolic acid copolymer matrix, whereinthe Class A corticosteroid comprises between 15% to 30% of themicroparticles; (iii) a population of microparticles comprising a ClassC corticosteroid or a pharmaceutically acceptable salt thereofincorporated in a lactic acid-glycolic acid copolymer matrix, whereinthe Class C corticosteroid comprises between 15% to 30% of themicroparticles; and (iv) a population of microparticles comprising aClass D corticosteroid or a pharmaceutically acceptable salt thereofincorporated in a lactic acid-glycolic acid copolymer matrix, whereinthe Class D corticosteroid comprises between 8% to 20% of themicroparticles. In some embodiments, the population of microparticlesreleases the corticosteroid for at least 14 days at a rate that does notadversely suppress the hypothalamic-pituitary-adrenal axis (HPA axis).In some embodiments, the population of microparticles releases thecorticosteroid in a controlled or sustained release manner such that thelevels of cortisol suppression are at or below 35% by day 14post-administration, for example post-administration. In someembodiments, the population of microparticles releases thecorticosteroid in a controlled or sustained release manner such that thelevels of cortisol suppression are negligible and/or undetectable by 14post-administration. In some embodiments, the population ofmicroparticles releases the corticosteroid in a controlled or sustainedrelease manner such that the levels of cortisol suppression arenegligible at any time post-administration.

The invention provides methods of treating pain or inflammation in apatient comprising administering to said patient a therapeuticallyeffective amount of a controlled or sustained release preparationselected from the following preparations: (i) a controlled or sustainedrelease preparation of a Class B corticosteroid comprising a lacticacid-glycolic acid copolymer microparticle containing the Class Bcorticosteroid, wherein the Class B corticosteroid comprises between 22%to 28% of the lactic acid-glycolic acid copolymer microparticle matrix;(ii) a controlled or sustained release preparation of a Class Acorticosteroid comprising a lactic acid-glycolic acid copolymermicroparticle containing the Class A corticosteroid, wherein the Class Acorticosteroid comprises between 15% to 30% of the lactic acid-glycolicacid copolymer microparticle matrix; (iii) a controlled or sustainedrelease preparation of a Class C corticosteroid comprising a lacticacid-glycolic acid copolymer microparticle containing the Class Ccorticosteroid, wherein the Class C corticosteroid comprises between 15%to 30% of the lactic acid-glycolic acid copolymer microparticle matrix;and (iv) a controlled or sustained release preparation of a Class Dcorticosteroid comprising a lactic acid-glycolic acid copolymermicroparticle containing the Class D corticosteroid, wherein the Class Dcorticosteroid comprises between 8% to 20% of the lactic acid-glycolicacid copolymer microparticle matrix. In some embodiments, the controlledor sustained release preparation releases the corticosteroid for atleast 14 days at a rate that does not adversely suppress thehypothalamic-pituitary-adrenal axis (HPA axis). In some embodiments, thecontrolled or sustained release preparation releases the corticosteroidin a controlled or sustained release manner such that the levels ofcortisol suppression are at or below 35% by day 14 post-administration,for example post-administration. In some embodiments, the controlled orsustained release preparation releases the corticosteroid in acontrolled or sustained release manner such that the levels of cortisolsuppression are negligible and/or undetectable by 14post-administration. In some embodiments, the controlled or sustainedrelease preparation releases the corticosteroid in a controlled orsustained release manner such that the levels of cortisol suppressionare negligible at any time post-administration.

The invention provides methods of treating pain or inflammation in apatient comprising administering to said patient a therapeuticallyeffective amount of a formulation selected from the followingpreparations: (i) a formulation comprising (a) controlled- or sustained-release microparticles comprising a Class B corticosteroid and a lacticacid-glycolic acid copolymer matrix, wherein the Class B corticosteroidcomprises between 22% to 28% of the microparticles and wherein thelactic acid-glycolic acid copolymer has one of more of the followingcharacteristics: (1) a molecular weight in the range of about 40 to 70kDa; (2) an inherent viscosity in the range of 0.5 to 0.5 dL/g; or (3) alactide:glycolide molar ratio of 80:20 to 60:40; (ii) a formulationcomprising (a) controlled- or sustained-release microparticlescomprising a Class A corticosteroid and a lactic acid-glycolic acidcopolymer matrix, wherein the Class A corticosteroid comprises between15% to 30% of the microparticles and wherein the lactic acid-glycolicacid copolymer has one of more of the following characteristics: (1) amolecular weight in the range of about 40 to 70 kDa; (2) an inherentviscosity in the range of 0.35 to 0.5 dL/g; or (3) a lactide:glycolidemolar ratio of 60:40 to 45:55; (iii) a formulation comprising (a)controlled- or sustained- release microparticles comprising a Class Ccorticosteroid and a lactic acid-glycolic acid copolymer matrix, whereinthe Class C corticosteroid comprises between 15% to 30% of themicroparticles and wherein the lactic acid-glycolic acid copolymer hasone of more of the following characteristics: (1) a molecular weight inthe range of about 40 to 70 kDa; (2) an inherent viscosity in the rangeof 0.35 to 0.5 dL/g; or (3) a lactide:glycolide molar ratio of 60:40 to45:55; and (iv) a formulation comprising (a) controlled- or sustained-release microparticles comprising a Class D corticosteroid and a lacticacid-glycolic acid copolymer matrix, wherein the Class D corticosteroidcomprises between 8% to 20% of the microparticles and wherein the lacticacid-glycolic acid copolymer has one of more of the followingcharacteristics: (1) a molecular weight in the range of about 40 to 70kDa; (2) an inherent viscosity in the range of 0.35 to 0.5 dL/g; or (3)a lactide:glycolide molar ratio of 60:40 to 45:55. In some embodiments,the formulation releases the corticosteroid for at least 14 days at arate that does not adversely suppress the hypothalamic-pituitary-adrenalaxis (HPA axis). In some embodiments, the formulation releases thecorticosteroid in a controlled or sustained release manner such that thelevels of cortisol suppression are at or below 35% by day 14post-administration, for example post-administration. In someembodiments, the formulation releases the corticosteroid in a controlledor sustained release manner such that the levels of cortisol suppressionare negligible and/or undetectable by 14 post-administration. In someembodiments, the formulation releases the corticosteroid in a controlledor sustained release manner such that the levels of cortisol suppressionare negligible at any time post-administration.

In some embodiments, the population of microparticles, the controlled orsustained release preparation or formulation is administered as one ormore intra-articular injections. In some embodiments, the patient hasosteoarthritis, rheumatoid arthritis, acute gouty arthritis, andsynovitis. In some embodiments, the patient has acute bursitis,sub-acute bursitis, acute nonspecific tenosynovitis, or epicondylitis.

In one aspect, a method of treating pain and/or inflammation in a jointof a patient is provided that includes administering intra-articularly(e.g., by one or more injections) to a patient with joint disease (e.g.,osteoarthritis or rheumatoid arthritis) a formulation that contains oneor more corticosteroids, such as those formulations described herein.Therapeutically effective amounts of the one or more corticosteroids arereleased for a period of time at a rate that does not suppress (e.g.,adversely and/or measurably) the HPA axis.

In another aspect, a method of treating pain and/or inflammation in ajoint of a patient is provided that includes administeringintra-articularly (e.g., by one or more injections) a therapeuticallyeffective amount of one or more corticosteroids in a formulation to apatient with joint disease (e.g., osteoarthritis or rheumatoidarthritis). The formulation has a sustained release microparticleformulation that may or may not release detectable levels ofcorticosteroid for a length of time following administration and thatreleases a detectable amount of corticosteroid(s) followingadministration, where the rate of corticosteroid release from thesustained release microparticle formulation does not adversely suppressthe HPA axis. In some embodiments, corticosteroid released from thesustained release microparticle formulation will not measurably suppressthe HPA axis.

According to certain embodiments of the foregoing methods, theformulation comprises a population of biodegradable polymermicroparticles that contain the corticosteroids. In some embodiments,the corticosteroids are 2% to 75% (w/w) of the microparticles,preferably about 5% to 50% (w/w) of the microparticles, and morepreferably 5% to 40% or 10% to 30% (w/w) of the microparticles. In someembodiments, the microparticles have a mass mean diameter of between 10μm to 100 μm. In some embodiments, the microparticles are formed from ahydrogel, hyaluronic acid, PLA or PLGA. For example, the microparticlesare formed from PLGA with a lactide to glycolide co-polymer ratio ofabout 45:55 to about 80:20. In some embodiments, the corticosteroid isbetamethasone, dexamethasone, triamcinolone acetonide, triamcinolonehexacetonide, prednisolone, methylprednisolone, budenoside, mometasone,ciclesonide, fluticasone, salts thereof, esters thereof or combinationsthereof.

In yet another aspect, a composition is provided that includes apopulation of biodegradable polymer microparticles that containcorticosteroid(s). For example, the corticosteroid is betamethasone,dexamethasone, triamcinolone acetonide, triamcinolone hexacetonide,prednisolone, methylprednisolone, budenoside, mometasone, ciclesonide,fluticasone, salts thereof, esters thereof or combinations thereof. Whenthe composition is administered intra-articularly (e.g., by one or moreinjections), a therapeutically effective amount of corticosteroid(s) isreleased for a period of time at a rate that does not suppress the HPAaxis. In some embodiments, the corticosteroid(s) released will notadversely suppress the HPA axis. In some embodiments, thecorticosteroid(s) released will not measurably suppress the HPA axis.

In yet a further aspect, a composition is provided that includes apopulation of biodegradable polymer microparticles that containcorticosteroid(s). For example, the corticosteroid is betamethasone,dexamethasone, triamcinolone acetonide, triamcinolone hexacetonide,prednisolone, methylprednisolone, budenoside, mometasone, ciclesonide,fluticasone, salts thereof, esters thereof or combinations thereof. Whenthe composition is administered intra-articularly (e.g., by one or moreinjections), therapeutically effective amounts of corticosteroid(s) arereleased following administration from a first component for a firstlength of time and from a sustained release component for a secondlength of time. Furthermore, the rate of corticosteroid(s) released fromthe sustained release component does not suppress the HPA axis. In someembodiments, the corticosteroid(s) released from the sustained releasecomponent during the second length of time will not adversely suppressthe HPA axis. In some embodiments, the corticosteroid(s) released fromthe sustained release component during the second length of time willnot measurably suppress the HPA axis. In some embodiments, the firstcomponent comprises a corticosteroid containing solution or suspension.In some embodiments, the first component contains a corticosteroid thatis different from that of the sustained release component. In otherembodiments, the same corticosteroid is used in both the first andsustained release components.

According to certain embodiments of the foregoing compositions, thecorticosteroids are 2% to 75% (w/w) of the microparticles, preferablyabout 5% to 50% (w/w) of the microparticles, and more preferably 5% to40% (w/w) of the microparticles. In some embodiments, the microparticleshave a mass mean diameter of between 10 μm to 100 μm. In someembodiments, the microparticles are formed from a hydrogel, hyaluronicacid, PLA or PLGA. For example, the microparticles are formed from PLGAwith a lactide to glycolide co-polymer ratio of about 45:55 to about80:20. In some embodiments, the compositions further comprise acorticosteroid containing solution or suspension. In some embodiments,the corticosteroid containing solution or suspension contains acorticosteroid that is different from that found in the microparticles.

The invention also provides methods of slowing, arresting or reversingprogressive structural tissue damage associated with chronicinflammatory disease in a patient comprising administering to saidpatient a therapeutically effective amount of a population ofmicroparticles selected from the following populations: (i) a populationof microparticles comprising a Class B corticosteroid or apharmaceutically acceptable salt thereof incorporated in a lacticacid-glycolic acid copolymer matrix, wherein the Class B corticosteroidcomprises between 22% to 28% of the microparticles; (ii) a population ofmicroparticles comprising a Class A corticosteroid or a pharmaceuticallyacceptable salt thereof incorporated in a lactic acid-glycolic acidcopolymer matrix, wherein the Class A corticosteroid comprises between15% to 30% of the microparticles; (iii) a population of microparticlescomprising a Class C corticosteroid or a pharmaceutically acceptablesalt thereof incorporated in a lactic acid-glycolic acid copolymermatrix, wherein the Class C corticosteroid comprises between 15% to 30%of the microparticles; and (iv) a population of microparticlescomprising a Class D corticosteroid or a pharmaceutically acceptablesalt thereof incorporated in a lactic acid-glycolic acid copolymermatrix, wherein the Class D corticosteroid comprises between 8% to 20%of the microparticles. In some embodiments, the population ofmicroparticles releases the corticosteroid for at least 14 days at arate that does not adversely suppress the hypothalamic-pituitary-adrenalaxis (HPA axis).

The invention also provides methods of slowing, arresting or reversingprogressive structural tissue damage associated with chronicinflammatory disease in a patient comprising administering to saidpatient a therapeutically effective amount of a controlled or sustainedrelease preparation selected from the following preparations: (i) acontrolled or sustained release preparation of a Class B corticosteroidcomprising a lactic acid-glycolic acid copolymer microparticlecontaining the Class B corticosteroid, wherein the Class Bcorticosteroid comprises between 22% to 28% of the lactic acid-glycolicacid copolymer microparticle matrix; (ii) a controlled or sustainedrelease preparation of a Class A corticosteroid comprising a lacticacid-glycolic acid copolymer microparticle containing the Class Acorticosteroid, wherein the Class A corticosteroid comprises between 15%to 30% of the lactic acid-glycolic acid copolymer microparticle matrix;(iii) a controlled or sustained release preparation of a Class Ccorticosteroid comprising a lactic acid-glycolic acid copolymermicroparticle containing the Class C corticosteroid, wherein the Class Ccorticosteroid comprises between 15% to 30% of the lactic acid-glycolicacid copolymer microparticle matrix; and (iv) a controlled or sustainedrelease preparation of a Class D corticosteroid comprising a lacticacid-glycolic acid copolymer microparticle containing the Class Dcorticosteroid, wherein the Class D corticosteroid comprises between 8%to 20% of the lactic acid-glycolic acid copolymer microparticle matrix.In some embodiments, the controlled or sustained release preparationreleases the corticosteroid for at least 14 days at a rate that does notadversely suppress the hypothalamic-pituitary-adrenal axis (HPA axis).

The invention also provides methods of slowing, arresting or reversingprogressive structural tissue damage associated with chronicinflammatory disease in a patient comprising administering to saidpatient a therapeutically effective amount of a formulation selectedfrom the following preparations: (i) a formulation comprising (a)controlled- or sustained-release microparticles comprising a Class Bcorticosteroid and a lactic acid-glycolic acid copolymer matrix, whereinthe Class B corticosteroid comprises between 22% to 28% of themicroparticles and wherein the lactic acid-glycolic acid copolymer hasone of more of the following characteristics: (1) a molecular weight inthe range of about 40 to 70 kDa; (2) an inherent viscosity in the rangeof 0.3 to 0.5 dL/g; or (3) a lactide:glycolide molar ratio of 80:20 to60:40; (ii) a formulation comprising (a) controlled- orsustained-release microparticles comprising a Class A corticosteroid anda lactic acid-glycolic acid copolymer matrix, wherein the Class Acorticosteroid comprises between 15% to 30% of the microparticles andwherein the lactic acid-glycolic acid copolymer has one of more of thefollowing characteristics: (1) a molecular weight in the range of about40 to 70 kDa; (2) an inherent viscosity in the range of 0.35 to 0.5dL/g; or (3) a lactide:glycolide molar ratio of 60:40 to 50:50; (iii) aformulation comprising (a) controlled- or sustained- releasemicroparticles comprising a Class C corticosteroid and a lacticacid-glycolic acid copolymer matrix, wherein the Class C corticosteroidcomprises between 15% to 30% of the microparticles and wherein thelactic acid-glycolic acid copolymer has one of more of the followingcharacteristics: (1) a molecular weight in the range of about 40 to 70kDa; (2) an inherent viscosity in the range of 0.35 to 0.5 dL/g; or (3)a lactide:glycolide molar ratio of 60:40 to 50:50; and (iv) aformulation comprising (a) controlled- or sustained-releasemicroparticles comprising a Class D corticosteroid and a lacticacid-glycolic acid copolymer matrix, wherein the Class D corticosteroidcomprises between 8% to 20% of the microparticles and wherein the lacticacid-glycolic acid copolymer has one of more of the followingcharacteristics: (1) a molecular weight in the range of about 40 to 70kDa; (2) an inherent viscosity in the range of 0.35 to 0.5 dL/g; or (3)a lactide:glycolide molar ratio of 60:40 to 50:50. In some embodiments,the formulation releases the corticosteroid for at least 14 days at arate that does not adversely suppress the hypothalamic-pituitary-adrenalaxis (HPA axis).

In some embodiments, the population of microparticles, the controlled orsustained release preparation or formulation is administered as one ormore intra-articular injections. In some embodiments, the patient hasosteoarthritis, rheumatoid arthritis, acute gouty arthritis, andsynovitis. In some embodiments, the patient has acute bursitis,sub-acute bursitis, acute nonspecific tenosynovitis, or epicondylitis.

The invention also provides methods to slow, arrest, reverse orotherwise inhibit progressive structural tissue damage associated withchronic inflammatory disease, for example, damage to cartilageassociated with osteoarthritis. In one embodiment, the method includesthe administration to a patient, for example local administration, of atherapeutically effective amount of one or more corticosteroids in aformulation, wherein the formulation releases the corticosteroid(s) forat least 14 days at a rate that does not adversely suppress thehypothalamic-pituitary-adrenal axis (HPA axis). The methods to assessthe effect of corticosteroid formulations on disease progression includecontrolled clinical studies that assess clinical end points and/oremploy imaging technologies such as, for example Magnetic ResonanceImaging (MM), to determine effects on the structure in chronicallyinflamed tissues, for example the effects on cartilage volume and otherarticular and peri-articular structures in osteoarthritis and rheumatoidarthritis. (See e.g., Eckstein F, et al. “Magnetic resonance imaging(MRI) of articular cartilage in knee osteoarthritis (OA): morphologicalassessment.” Osteoarthritis Cartilage 14 Suppl A (2006): A46-75; Lo GH,et al. “Bone marrow lesions in the knee are associated with increasedlocal bone density.” Arthritis Rheum 52 (2005): 2814-21; and Lo GH, etal. “The ratio of medial to lateral tibial plateau bone mineral densityand compartment-specific tibiofemoral osteoarthritis.” OsteoarthritisCartilage 14 (2006): 984-90 the contents of each of which are herebyincorporated by reference in their entirety.) The corticosteroidmicroparticle formulations provided herein appear to exhibit little tono negative effects, e.g., structural tissue damage, and frompreliminary data and studies described in the Examples below, thesecorticosteroid microparticle formulations appear to have a positiveeffect, e.g., slowing, arresting or reversing structural tissue damage.

The invention also provides methods of treating pain and/or inflammationof a patient by administering to the patient a therapeutically effectiveamount of one or more corticosteroids in a formulation, wherein theformulation releases the corticosteroid(s) for at least 14 days at arate that does not adversely suppress the hypothalamic-pituitary-adrenalaxis (HPA axis).

The invention also provides methods of manufacturing the corticosteroidmicroparticle formulations. The microparticle formulations providedherein can be manufactured using any of a variety of suitable methods.

For the Class B corticosteroid microparticle formulations, in someembodiments, the microparticles are manufactured as described in theExamples provided below. For the Class B corticosteroid microparticleformulations, in some embodiments, the microparticles are manufacturedas described in U.S. Pat. No. 7,261,529 and U.S. Pat. No. 7,758,778, thecontents of each of which are hereby incorporated by reference in theirentirety. For example, the microparticles are manufactured using asolvent evaporation process wherein the Class B corticosteroid isdispersed in a lactic acid-glycolic acid copolymer organic solution andthe mixture is treated to remove the solvent from the mixture, therebyproducing microparticles.

In some embodiments, the solvent evaporation process utilizes a spraydrying or fluid bed apparatus to remove the solvent and producemicroparticles. In some embodiments, the solvent evaporation processutilizes a spinning disk. For example, the spinning disk is the spinningdisk as described in U.S. Pat. No. 7,261,529 and U.S. Pat. No.7,758,778.

For the Class B corticosteroid microparticle formulations, in someembodiments where the Class B corticosteroid is TCA, the microparticlesare manufactured using a solid in oil in water emulsion process whereinTCA is dispersed in a lactic acid-glycolic acid copolymer organicsolution and added to an aqueous solvent to produce microparticles.

For the Class A, C and/or D corticosteroid microparticle formulations,in some embodiments, the microparticles are manufactured as described inthe Examples provided below. For Class A, C and/or D corticosteroidformulations, in some embodiments, the microparticles are manufacturedas described in PCT Publication No. WO 95/13799, the contents of whichare hereby incorporated by reference in their entirety. For example, themicroparticles are manufactured using a solid in oil in water emulsionprocess wherein the Class A corticosteroid, Class C corticosteroidand/or Class D corticosteroid is dispersed in a lactic acid-glycolicacid copolymer organic solution and added to an aqueous solvent toproduce microparticles.

It is contemplated that whenever appropriate, any embodiment of thepresent invention can be combined with one or more other embodiments ofthe present invention, even though the embodiments are described underdifferent aspects of the present invention.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a graph depicting the intra-articular concentrations (topsolid line) and the systemic concentrations (bottom solid line) of theglucocorticoid administered according to certain embodiments of thepresent invention following intra-articular injection. The systemicglucocorticoid concentration associated with clinically significantsuppression of the HPA axis is shown as the bottom dotted line. The topdotted line represents the minimal intra-articular concentrationrequired to maintain efficacy (defined as relief of pain andinflammation, or slowing, arrest, or reversal of structural damage totissues caused by inflammatory diseases. Sustained release of thecorticosteroid provides sufficient intra-articular concentrations tomaintain efficacy in the longer term, and has transient, clinicallyinsignificant effect on the HPA axis.

FIG. 2 is a graph depicting the change in sensitivity over time tosuppression of endogenous cortisol production (EC₅₀ (ng/mL) vs. time)for triamcinolone acetonide 40 mg given by intra-articularadministration.

FIG. 3 is a graph depicting the change in sensitivity over time tosuppression of endogenous cortisol production (EC₅₀ (ng/mL) vs. time)for various corticosteroids administered as a single, intra-articularinjection in the listed dose.

FIGS. 4A-4F are a series of graphs depicting plasma levels of endogenouscortisol over time, without (FIGS. 4A, 4C, and 4E) adjustment for achange in the sensitivity of the HPA axis after intra-articularcorticosteroids and with (FIGS. 4B, 4D, and 4F) adjustment for a changein the sensitivity of the HPA axis after intra-articularcorticosteroids. These data demonstrate that the sensitivity of the HPAaxis varies with corticosteroid, dose, and time with clinicallyimportant implications for the selection of doses for sustained deliveryinto an intra-articular space.

FIG. 5 is a graph depicting the cumulative percent release of a nominal25% (w/w) triamcinolone acetonide in PLGA 75:25 microparticles.

FIG. 6 is a graph depicting the calculated human dose to achievetransient cortisol suppression and within 14 days achieve less than 35%cortisol suppression using nominal 25% TCA PLGA 75:25 microparticles.The dotted lines represent, from top to bottom of the graph, 50%cortisol inhibition dose, 40% cortisol inhibition dose, 35% cortisolinhibition dose and 5% cortisol inhibition dose.

FIG. 7 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 25% TCAPLGA 75:25 microparticles. The dotted lines represent, from top tobottom of the graph, 50% cortisol inhibition dose, 40% cortisolinhibition dose, 35% cortisol inhibition dose and 5% cortisol inhibitiondose.

FIG. 8 is a graph depicting cumulative percent release of a secondpreparation of nominal 25% triamcinolone acetonide in PLGA 75:25microparticles using an alternate preparation.

FIG. 9 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using a second preparation of nominal 25% TCA PLGA 75:25microparticles made by an alternate preparation. The dotted linesrepresent, from top to bottom of the graph, 50% cortisol inhibitiondose, 40% cortisol inhibition dose, 35% cortisol inhibition dose and 5%cortisol inhibition dose.

FIG. 10 is a graph depicting: calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using a secondpreparation of nominal 25% TCA PLGA 75:25 microparticles made by analternate preparation. The dotted lines represent, from top to bottom ofthe graph, 50% cortisol inhibition dose, 40% cortisol inhibition dose,35% cortisol inhibition dose and 5% cortisol inhibition dose.

FIG. 11 is a graph depicting cumulative percent release of nominal 25%triamcinolone acetonide in 5% PEG 1450/PLGA 75:25 microparticles.

FIG. 12 is a graph depicting cumulative percent release of nominal 25%triamcinolone acetonide in 10% PEG 3350/PLGA 75:25 microparticles.

FIG. 13 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using nominal 25% TCA 5% PEG 1450/PLGA 75:25 microparticles.The dotted lines represent, from top to bottom of the graph, 50%cortisol inhibition dose, 40% cortisol inhibition dose, 35% cortisolinhibition dose and 5% cortisol inhibition dose.

FIG. 14 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using nominal 25% TCA 10% PEG 3350/PLGA 75:25microparticles. The dotted lines represent, from top to bottom of thegraph, 50% cortisol inhibition dose, 40% cortisol inhibition dose, 35%cortisol inhibition dose and 5% cortisol inhibition dose.

FIG. 15 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 25% TCA5% PEG 1450/PLGA 75:25 microparticles. The dotted lines represent, fromtop to bottom of the graph, 50% cortisol inhibition dose, 40% cortisolinhibition dose, 35% cortisol inhibition dose and 5% cortisol inhibitiondose.

FIG. 16 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 25% TCA10% PEG 3350/PLGA 75:25 microparticles. The dotted lines represent, fromtop to bottom of the graph, 50% cortisol inhibition dose, 40% cortisolinhibition dose, 35% cortisol inhibition dose and 5% cortisol inhibitiondose.

FIG. 17 is a graph depicting cumulative percent triamcinolone acetoniderelease of nominal 40%, 25% 20%, 15% and 10% TCA containing PLGA 75:25microparticles.

FIG. 18 is a graph depicting cumulative percent release of nominal 25%TCA PLGA 75:25 (29 kDa) and PLGA 75:25 (54 kDa) containingmicroparticles.

FIG. 19 is a graph depicting cumulative percent release of triamcinoloneacetonide in PLGA 50:50 microparticle formulations.

FIG. 20 is a graph depicting cumulative percent release of nominal 28.6%triamcinolone acetonide in PLGA 75:25 plus Triblock microparticleformulations.

FIG. 21 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using nominal 28.6% TCA 10% Triblock/PLGA 75:25microparticles. The dotted lines represent, from top to bottom of thegraph, 50% cortisol inhibition dose, 40% cortisol inhibition dose, 35%cortisol inhibition dose and 5% cortisol inhibition dose.

FIG. 22 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using nominal 28.6% TCA 20% Triblock/PLGA 75:25microparticles. The dotted lines represent, from top to bottom of thegraph, 50% cortisol inhibition dose, 40% cortisol inhibition dose, 35%cortisol inhibition dose and 5% cortisol inhibition dose.

FIG. 23 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 28.6% TCA10% Triblock/PLGA 75:25 microparticles. The dotted lines represent, fromtop to bottom of the graph, 50% cortisol inhibition dose, 40% cortisolinhibition dose, 35% cortisol inhibition dose and 5% cortisol inhibitiondose.

FIG. 24 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 28.6% TCA20% Triblock/PLGA 75:25 microparticles. The dotted lines represent, fromtop to bottom of the graph, 50% cortisol inhibition dose, 40% cortisolinhibition dose, 35% cortisol inhibition dose and 5% cortisol inhibitiondose.

FIG. 25 is a graph depicting cumulative percent release of nominal 16.7%triamcinolone acetonide in mixed molecular weight PLGA 75:25microparticle formulations.

FIG. 26 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using nominal 16.7% TCA mixed molecular weight PLGA 75:25microparticles. The dotted lines represent, from top to bottom of thegraph, 50% cortisol inhibition dose, 40% cortisol inhibition dose, 35%cortisol inhibition dose and 5% cortisol inhibition dose.

FIG. 27 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 16.7% TCAmixed molecular weight PLGA 75:25 microparticles. The dotted linesrepresent, from top to bottom of the graph, 50% cortisol inhibitiondose, 40% cortisol inhibition dose, 35% cortisol inhibition dose and 5%cortisol inhibition dose.

FIG. 28 is a graph depicting cumulative percent release of nominal 28.6%triamcinolone acetonide in various polymer microparticle formulations.

FIG. 29 is a graph depicting cumulative percent release of nominal 28.6%Prednisolone in PLGA 50:50 microparticle formulation.

FIG. 30 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using nominal 28.6% PRED PLGA 50:50 microparticles. Thedotted lines represent, from top to bottom of the graph, 50% cortisolinhibition dose, 40% cortisol inhibition dose, 35% cortisol inhibitiondose and 5% cortisol inhibition dose.

FIG. 31 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 28.6%PRED PLGA 50:50 microparticles. The dotted lines represent, from top tobottom of the graph, 50% cortisol inhibition dose, 40% cortisolinhibition dose, 35% cortisol inhibition dose and 5% cortisol inhibitiondose.

FIG. 32 is a graph depicting cumulative percent release of nominal 28.6%Betamethasone PLGA 50:50 microparticle formulation.

FIG. 33 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using nominal 28.6% BETA PLGA 50:50 microparticles. Thedotted lines represent, from top to bottom of the graph, 50% cortisolinhibition dose, 40% cortisol inhibition dose, 35% cortisol inhibitiondose and 5% cortisol inhibition dose.

FIG. 34 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 28.6%BETA PLGA 50:50 microparticles. The dotted lines represent, from top tobottom of the graph, 50% cortisol inhibition dose, 40% cortisolinhibition dose, 35% cortisol inhibition dose and 5% cortisol inhibitiondose.

FIG. 35 is a graph depicting cumulative percent release of nominal 16.7%Fluticasone Propionate PLGA 50:50 microparticle formulation.

FIG. 36 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression using nominal 16.7% FLUT PLGA 50:50 microparticles. Thedotted lines represent, from top to bottom of the graph, 50% cortisolinhibition dose, 40% cortisol inhibition dose, 35% cortisol inhibitiondose and 5% cortisol inhibition dose.

FIG. 37 is a graph depicting calculated human dose that does not affectthe HPA axis, less than 35% cortisol suppression using nominal 16.7%FLUT PLGA 50:50 microparticles. The dotted lines represent, from top tobottom of the graph, 50% cortisol inhibition dose, 40% cortisolinhibition dose, 35% cortisol inhibition dose and 5% cortisol inhibitiondose.

FIG. 38 is a graph depicting cumulative percent release of variousFluticasone Propionate PLGA microparticle formulations.

FIG. 39 is a graph depicting cumulative percent release of nominal 28.6%DEX PLGA 50:50 microparticle formulation.

FIG. 40 is a graph depicting calculated human dose to achieve transientcortisol suppression and within 14 days achieve less than 35% cortisolsuppression and does not affect the HPA axis, less than 35% cortisolsuppression using nominal 28.6% DEX PLGA 50:50 microparticles. Thedotted lines represent, from top to bottom of the graph, 50% cortisolinhibition dose, 40% cortisol inhibition dose, 35% cortisol inhibitiondose and 5% cortisol inhibition dose.

FIGS. 41A-41D are a series of graphs depicting the meanconcentration-time profiles of various doses of TCA IR and FX006 in ratplasma following single intra-articular doses. A microparticleformulation of TCA in 75:25 PLGA formulation microparticles, referred toas FX006, dosed at 1.125 mg resulted in a very slow absorption of TCA inthe systemic circulation and a markedly lower Cmax as compared to TCAIR. Concentrations for the first 72 hr are presented in FIGS. 41C and41D on a larger time scale.

FIG. 42 is a graph depicting corticosteroid inhibition and recovery withTCA IR (immediate release) and FX006 (microparticle formulation) inrats.

FIG. 43 is a graph depicting the pharmacokinetic/pharmacodynamic (PK/PD)relationship of systemic TCA levels and corticosterone inhibition.

FIGS. 44A-44C are a series of graphs depicting the gait analysis scores,an indicator of pain, in rats injected with doses of either immediaterelease triamcinolone acetonide (TCA IR) or TCA microparticles (FX006)in a model of osteoarthritis. In FIG. 44A, FX006 at 0.28, 0.12 and 0.03mg (TCA doses) is expressed as TCA concentrations of the dosingformulation (4.67, 2 and 0.5 mg/ml). In FIG. 44B, FX006 at 0.28 mg (TCAdose) is expressed as TCA concentrations of the dosing formulation (4.67mg/ml). Similarly, TCA IR at 0.03 mg is expressed as triamcinolone at0.5 mg/ml. In FIG. 44C, FX006 at 0.28, 0.12 and 0.03 mg (TCA doses) isexpressed as TCA concentrations of the dosing formulation (4.67, 2 and0.5 mg/ml). Similarly, TCA IR at 0.06 and 0.03 mg is expressed astriamcinolone at 1 and 0.5 mg/ml.

FIG. 45 is a graph depicting peak pain response following repeatedreactivations of arthritis in the right knee. All treatments wereadministered as a single IA dose in the right knee on Day 0.

FIG. 46 is a graph depicting the time course of corticosterone recoveryfor various groups in the rat study in a model of osteoarthritis.

FIGS. 47A-47B are a series of graphs depicting the plasma TCAconcentration-time data for various groups in the rat study in a modelof osteoarthritis. Only the groups that received injections of TCAmicroparticles (FX006 groups) are shown in FIG. 47B on an expandedscale.

FIG. 48 is a graph depicting the end-of-study histopathology scores forvarious treatment groups in the rat study in a model of osteoarthritis.

DETAILED DESCRIPTION OF THE INVENTION

The invention provides compositions and methods for the treatment ofpain and inflammation using corticosteroids. The compositions andmethods provided herein use one or more corticosteroids in amicroparticle formulation. The corticosteroid microparticle formulationsprovided herein are effective at treating pain and/or inflammation withminimal prolonged suppression of the HPA axis and/or other long termside effects of corticosteroid administration. The corticosteroidmicroparticle formulations provided herein are effective in slowing,arresting, reversing or otherwise inhibiting structural damage totissues associated with progressive disease with minimal prolongedsuppression of the HPA axis and/or other long term side effects ofcorticosteroid administration. The corticosteroid microparticleformulations provided herein deliver the corticosteroid in a dose and ina sustained release manner such that the levels of cortisol suppressionare at or below 35% by day 14 post-injection. In some embodiments, thecorticosteroid microparticle formulations provided herein deliver thecorticosteroid in a dose and in a controlled or sustained release mannersuch that the levels of cortisol suppression are negligible and/orundetectable by 14 post-injection. Thus, the corticosteroidmicroparticle formulations in these embodiments are effective in theabsence of any significant HPA axis suppression. Administration of thecorticosteroid microparticle formulations provided herein can result inan initial “burst” of HPA axis suppression, for example, within thefirst few days, within the first two days and/or within the first 24hours post-injection, but by day 14 post-injection, suppression of theHPA axis is less than 35%.

The use of microparticles to administer corticosteroids is known (See,e.g., U.S. Patent Application Publication. No. 20080317805). Inaddition, corticosteroids are known to be useful for the symptomatictreatment of inflammation and pain. New data also suggest that synovitismay be associated with the structural damage, for example, thedeterioration of cartilage and other peri-articular associated with theprogression of osteoarthritis and rheumatoid arthritis. (See e.g., HillC L, et al. “Synovitis detected on magnetic resonance imaging and itsrelation to pain and cartilage loss in knee osteoarthritis.” Ann RheumDis 66 (2007):1599-603; van den Berg W B, et al. “Synovial mediators ofcartilage damage and repair in osteoarthritis.” In: Brandt KD, DohertyM, Lohmander L S, eds. Osteoarthritis. Second ed. Oxford: OxfordUniversity Press (2003):147-55; Ayral X, et al. “Synovitis: a potentialpredictive factor of structural progression of medial tibiofemoral kneeosteoarthritis—results of a 1 year longitudinal arthroscopic study in422 patients.” Osteoarthritis Cartilage 13 (2005):361-7; and Kirwan JR,et al. “Effects of glucocorticoids on radiological progression inrheumatoid arthritis.” Cochrane Database Syst Rev 2007:CD006356).

The administration of corticosteroids, particularly for extended periodsof time, can have a number of unwanted side effects. The HPA axis, theinterdependent feedback mechanism between the hypothalamus, thepituitary gland and the adrenal cortex, may be suppressed by theadministration of corticosteroids, leading to a variety of unwanted sideeffects. The extent of HPA axis suppression, and related inhibition ofendogenous cortisol production, has been attributed to the potency ofthe corticosteroid, the dose, systemic concentration, protein binding,rate of elimination (Meibohm et al. “Mechanism-based PK/PD model for thelymphocytopenia induced by endogenous and exogenous corticosteroids.”Int J Clin Pharmacol Ther. 37(8) (1999):367-76) and, for onecorticosteroid, a change in sensitivity of the HPA axis (Derendorf etal. “Clinical PK/PD modelling as a tool in drug development ofcorticosteroids.” Int J. Clin Pharmacol Ther. 35(10) 1997: 481-8).Furthermore, intra-articular doses of corticosteroids associated withonly limited anti-inflammatory and short-term analgesic benefit (Hepperet al. “The efficacy and duration of intra-articular corticosteroidinjection for knee osteoarthritis: a systematic review of level Istudies.” J Am Acad Orthop Surg. 17(10) 2009: 638-46) have beenassociated with HPA axis suppression (Habib, “Systemic effects ofintra-articular corticosteroids.” Clin Rheumatol. 28(7) (2009): 749-56).

The changes in sensitivity to corticosteroid effects over time shouldalter clinical steroid dosing, but prior to the instant invention, thishas not been understood.

The details of one or more embodiments of the invention are set forth inthe accompanying description below. Although any methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present invention, the methods and materialsare now described. Other features, objects, and advantages of theinvention will be apparent from the description. In the specification,the singular forms also include the plural unless the context clearlydictates otherwise. Unless defined otherwise, all technical andscientific terms used herein have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. In the case of conflict, the present Specification willcontrol.

Definitions

The terms below have the following meanings unless indicated otherwise.

An amount of a corticosteroid that does not “suppress thehypothalamic-pituitary-adrenal axis (HPA axis)” refers to the amount ofthe sustained release corticosteroid delivered locally to relieve paindue to inflammation, which provides a systemic concentration that willnot have a clinically significant effect or “adverse effect” on the HPAaxis. Suppression of the HPA axis is generally manifested by a reductionin endogenous glucocorticoid production. It is useful to consider bothbasal and augmented production of endogenous glucocorticoids. Underordinary, “unstressed” conditions, glucocorticoid production occurs at anormal, basal level. There is some natural variation of productionduring the course of the 24-hour day. Under extraordinary, “stressed”conditions associated with, e.g., infection or trauma and the like,augmented endogenous production of glucocorticoids occurs. Endogenouscortisol production may be determined by measuring glucocorticoidconcentrations in plasma, saliva, urine or by any other means known inthe art. It is known that systemic concentrations of corticosteroids cansuppress the HPA axis. For example, on day 3 after an intra-articularinjection of 20 mg triamcinolone hexacetonide plasma levels, ofapproximately 3-4 ng/mL have been observed. These resulted in atransient but highly statistically significant 75% HPA-axis suppression(Derendorf et al., “Pharmacokinetics and pharmacodynamics ofglucocorticoid suspensions after intra-articular administration.” ClinPharmacol Ther. 39(3) (1986):313-7) which, however, does not necessarilyportend complete HPA failure (Habib, “Systemic effects ofintra-articular corticosteroids.” Clin Rheumatol 28 (2009): 749-756, seep752 col. 1, para 2, final sentence). While such transient suppressionis generally considered to be acceptable without clinically significanteffect, more persistent suppression, i.e., weeks, would be deemedclinically detrimental. In embodiments of the present invention,administration of the formulation may result in a clinically acceptableHPA suppression, particularly during the initial release period of thetherapy. In some embodiments of the present invention, administration ofthe formulation will not result in any significant level of HPAsuppression, including no detectable HPA suppression, particularlyduring the initial release period of the therapy. During the subsequentor sustained release period of the therapy, additional corticosteroidmay be released into the plasma. However, the plasma levels during thisperiod will generally be less than those during the initial releaseperiod, if any corticosteroid release occurs, and will not be associatedwith HPA axis suppression. Further, the adverse events associated withexogenous corticosteroid administration, e.g., hyperglycemia,hypertension, altered mood, etc. will generally not be observed.Preferably, the number of clinical adverse events during this periodwill not substantially exceed the number achieved by an immediaterelease formulation alone or by KENALOG™ or its bioequivalent and will,preferably, be fewer than during the prior, initial release period ofthe therapy, if any corticosteroid release occurs. Alternatively, onecan determine the suppression of the formulation on HPA by measuringendogenous cortisol production. Thus, the formulation can be consideredas avoiding clinically significant (or adverse) suppression of the HPAaxis where the endogenous cortisol level is substantially the same inthe steady state between a patient population receiving atherapeutically beneficial amount of an immediate release formulationand those receiving a therapeutically beneficial amount of a sustainedrelease formulation. Such a formulation would be deemed to have noclinically significant effect on the HPA axis. Alternatively oradditionally, a small but measurable reduction in steady-stateglucocorticoid production can result from the formulation during thesustained release period of the therapy with adequate preservation ofthe augmented, stress response needed during infection or trauma can bedeemed a clinically insignificant suppression of the HPA axis.Endogenous glucocorticoid production may be assessed by administeringvarious doses of adrenocorticotropin hormone or by other tests known tothose skilled in the art. Embodiments of the current invention providefor controlling the release of corticosteroid, as may be desired, toachieve either no measurable effect on endogenous glucocorticoidproduction or a target, or a measurable effect that is, however, withoutadverse clinical consequence. In this regard, it has been found thatintra-articular doses of corticosteroids that suppress cortisolproduction by 20-35%, and sometimes more, provide very useful sustainedanti-inflammatory and analgesic activity. These benefits are achievedwithout acute risks of hypoadrenalism and without excessive risks, aftersustained intra-articular dosing, of developing an adrenalunresponsiveness in times of stress or of developing frank adrenalfailure.

As shown further below, the studies presented herein have demonstratedthat the HPA axis sensitivity appears to diminish with time, steroid,and dose. In this regard, it has been determined that standard doses offamiliar corticosteroids, when examined from the viewpoint ofsteady-state HPA axis suppression (i.e., after desensitization hasoccurred), provide clinically useful benchmarks. For example, while oralprednisolone given at 20 mg QD produces a 73% cortisol suppression, even5 mg QD (considered a “low dose”) is associated with a 40% suppressionof endogenous cortisol production. Doses at or below 5 mg ofprednisolone per day are generally considered to be well tolerated andare not associated with clinically meaningful HPA axis suppression (LaRochelle et al., “Recovery of the hypothalamic-pituitary-adrenal (HPA)axis in patients with rheumatic diseases receiving low-doseprednisolone.” Am. J. Med. 95 (1993): 258-264). Therefore, up toapproximately 40% suppression will be clinically well tolerated and veryunlikely to be associated with importantly adverse clinical events suchas hypoadrenalism or soft-tissue or bony or metabolic changes indicativeof long-term glucocorticoid excess.

“Patient” refers to a human diagnosed with a disease or condition thatcan be treated in accordance to the inventions described herein. In someembodiments it is contemplated that the formulations described hereinmay also be used in horses.

“Delivery” refers to any means used to place the drug into a patient.Such means may include without limitation, placing matrices into apatient that release the drug into a target area. One of ordinary skillin the art recognizes that the matrices may be delivered by a widevariety of methods, e.g., injection by a syringe, placement into a drillsite, catheter or canula assembly, or forceful injection by a gun typeapparatus or by placement into a surgical site in a patient duringsurgery.

The terms “treatment” and “treating” a patient refer to reducing,alleviating, stopping, blocking, or preventing the symptoms of painand/or inflammation in a patient. As used herein, “treatment” and“treating” includes partial alleviation of symptoms as well as completealleviation of the symptoms for a time period. The time period can behours, days, months, or even years.

By an “effective” amount or a “therapeutically effective amount” of adrug or pharmacologically active agent is meant a nontoxic butsufficient amount of the drug or agent to provide the desired effect,e.g., analgesia. An appropriate “effective” amount in any individualcase may be determined by one of ordinary skill in the art using routineexperimentation.

“Site of a patient's pain” refers to any area within a body causingpain, e.g., a knee joint with osteoarthritis, nerve root causing sciaticpain, nerve fibers growing into annular tears in discs causing backpain, temporomandibular joint (TMJ) pain, for example TMJ painassociated with temporomandibular joint disorder (TMD) or pain radiatingfrom epidural or perineural spaces. The pain perceived by the patientmay result from inflammatory responses, mechanical stimuli, chemicalstimuli, thermal stimuli, as well as allodynia.

Additionally, the site of a patient's pain can comprise one or multiplesites in the spine, such as between the cervical, thoracic, or lumbarvertebrae, or can comprise one or multiple sites located within theimmediate area of inflamed or injured joints such as the shoulder, hip,or other joints.

A “biocompatible” material refers to a material that is not toxic to thehuman body, it is not carcinogenic and it should induce limited or noinflammation in body tissues. A “biodegradable” material refers to amaterial that is degraded by bodily processes (e.g., enzymatic) toproducts readily disposable by the body or absorbed into body tissue.The biodegraded products should also be biocompatible with the body. Inthe context of intra-articular drug delivery systems forcorticosteroids, such polymers may be used to fabricate, withoutlimitation: microparticles, micro-spheres, matrices, microparticlematrices, micro-sphere matrices, capsules, hydrogels, rods, wafers,pills, liposomes, fibers, pellets, or other appropriate pharmaceuticaldelivery compositions that a physician can administer into the joint.

The biodegradable polymers degrade into non-toxic residues that the bodyeasily removes or break down or dissolve slowly and are cleared from thebody intact. The polymers may be cured ex-vivo forming a solid matrixthat incorporates the drug for controlled release to an inflammatoryregion. Suitable biodegradable polymers may include, without limitationnatural or synthetic biocompatible biodegradable material. Naturalpolymers include, but are not limited to, proteins such as albumin,collagen, gelatin synthetic poly(aminoacids), and prolamines;glycosaminoglycans, such as hyaluronic acid and heparin;polysaccharides, such as alginates, chitosan, starch, and dextrans; andother naturally occurring or chemically modified biodegradable polymers.Synthetic biocompatible biodegradable materials include, but are notlimited to, poly(lactide-co-glycolide) (PLGA), polylactide (PLA),polyglycolide (PG), polyhydroxybutyric acid, poly(trimethylenecarbonate), polycaprolactone (PCL), polyvalerolactone,poly(alpha-hydroxy acids), poly(lactones), poly(amino-acids),poly(anhydrides), polyketals poly(arylates), poly(orthoesters),polyurethanes, polythioesters, poly(orthocarbonates),poly(phosphoesters), poly(ester-co-amide), poly(lactide-co-urethane,polyethylene glycol (PEG), polyvinyl alcohol (PVA), PVA-g-PLGA, PEGT-PBTcopolymer (polyactive), methacrylates, poly(N-i sopropylacrylamide),PEO-PPO-PEO (pluronics), PEO-PPO-PAA copolymers, and PLGA-PEO-PLGAblends and copolymers thereof and any combinations thereof. Thebiocompatible biodegradable material can include a combination ofbiocompatible biodegradable materials. For example, the biocompatiblebiodegradable material can be a triblock, or other multi-block,formation where a combination of biocompatible biodegradable polymersare joined together. For example, the triblock can be PLGA-PEG-PLGA.

Diseases That May be Treated Using the Formulations of This Invention

Descriptions of various embodiments of the invention are given below.Although these embodiments are exemplified with reference to treat jointpain associated with osteoarthritis, rheumatoid arthritis and otherjoint disorders, it should not be inferred that the invention is onlyfor these uses. Rather, it is contemplated that embodiments of thepresent invention will be useful for treating other forms of joint painby administration into articular and periarticular spaces. In addition,it will be understood that for some embodiments injection near a jointmay be equivalent to injections in that joint. It is also contemplatedthat embodiments of the present invention may be useful for injection oradministration into soft tissues or lesions. Any and all uses ofspecific words and references are simply to detail different embodimentsof the present invention.

Local administration of a corticosteroid microparticle formulation canoccur, for example, by injection into the intra-articular space,peri-articular space, soft tissues, lesions, epidural space, perineuralspace, or the foramenal space at or near the site of a patient's painand/or structural tissue damage. Local injection of the formulationsdescribed herein into articular or periarticular spaces may be useful inthe treatment of, for example, juvenile rheumatoid arthritis, sciaticaand other forms of radicular pain (e.g., arm, neck, lumbar, thorax),psoriatic arthritis, acute gouty arthritis, Morton's neuroma, acute andsubacute bursitis, acute and subacute nonspecific tenosynovitis andepicondylitis, acute rheumatic carditis and ankylosing spondylitis.Injection of the microparticles described herein into soft tissues orlesions may be useful in the treatment of, for example, alopecia areata,discoid lupus, erythematosus; keloids, localized hypertrophic,infiltrated inflammatory lesions of granuloma annulare, lichen planus,lichen simplex chronicus (neurodermatitis), psoriasis and psoriaticplaques; necrobiosis lipoidica diabeticorum, and psoriatic arthritis.Injection of the microparticles described herein into epidural spacesmay be useful in the treatment of, for example, neurogenic claudication.Intramuscular or other soft tissues or lesions injections may also beuseful in providing systemic exposures that are effective in the controlof incapacitating allergic conditions (including but not limited toasthma, atopic dermatitis, contact dermatitis, drug hypersensitivityreactions, seasonal or perennial allergic rhinitis, serum sickness,transfusion reactions), bullous dermatitis herpetiformis, exfoliativedermatitis, mycosis fungoides, pemphigus, severe erythema multiforme(Stevens-Johnson syndrome), Primary or secondary adrenocorticalinsufficiency in conjunction with mineralocorticoids where applicable;congenital adrenal hyperplasia, hypercalcemia associated with cancer,nonsupportive thyroiditis, exacerbations of regional enteritis andulcerative colitis, acquired (autoimmune) hemolytic anemia, congenital(erythroid) hypoplastic anemia (Diamond blackfan anemia), pure red cellaplasia, select cases of secondary thrombocytopenia, trichinosis withneurologic or myocardial involvement, tuberculous meningitis withsubarachnoid block or impending block when used concurrently withappropriate antituberculous chemotherapy, palliative management ofleukemias and lymphomas, acute exacerbations of multiple sclerosis,cerebral edema associated with primary or metastatic brain tumor orcraniotomy, to induce diuresis or remission of proteinuria in idiopathicnephrotic syndrome, or to induce diuresis or remission of proteinuria inlupus erythematosus, berylliosis, symptomatic sarcoidosis, fulminatingor disseminated pulmonary tuberculosis (when used concurrently withappropriate antituberculous chemotherapy), idiopathic eosinophilicpneumonias, symptomatic sarcoidosis, dermatomyositis, polymyositis, andsystemic lupus erythematosus, post-operative pain and swelling.

In one embodiment, the corticosteroid microparticle formulationsprovided herein are useful in treating, alleviating a symptom of,ameliorating and/or delaying the progression of sciatica. In oneembodiment, corticosteroid microparticle formulations provided hereinare useful in treating, alleviating a symptom of, ameliorating and/ordelaying the progression of temporomandibular joint disorder (TMD).

In one embodiment, the corticosteroid microparticle formulationsprovided herein are useful in treating, alleviating a symptom of,ameliorating and/or delaying the progression of neurogenic claudicationsecondary to lumbar spinal stenosis (LSS). LSS implies spinal canalnarrowing with possible subsequent neural compression (classified byanatomy or etiology). Neurogenic Claudication (NC) is a hallmark symptomof lumbar stenosis, in which the column of the spinal cord (or thecanals that protect the nerve roots) narrows at the lower back. Thisnarrowing can also occur in the spaces between the vertebrae where thenerves leave the spine to travel to other parts of the body.

The microparticles of the invention are used to treat, alleviate asymptom of, ameliorate and/or delay the progression patients sufferingfrom NC secondary to LSS. The corticosteroid microparticle formulationscan be administered, for example, by epidural steroid injection (ESI).

Administration of a corticosteroid microparticle formulation, e.g., aTCA microparticle formulation, to a patient suffering from aninflammatory disease such as osteoarthritis or rheumatoid arthritis, isconsidered successful if any of a variety of laboratory or clinicalresults is achieved. For example, administration of a corticosteroidmicroparticle formulation is considered successful if one or more of thesymptoms associated with the disease is alleviated, reduced, inhibitedor does not progress to a further, i.e., worse, state. Administration ofa corticosteroid microparticle formulation is considered successful ifthe disease, e.g., an arthritic or other inflammatory disease, entersremission or does not progress to a further, i.e., worse, state.

Also, any and all alterations and further modifications of theinvention, as would occur to one of ordinary skill in the art, areintended to be within the scope of the invention

Selection of Corticosteroids and Drug Dosage

Corticosteroids associated with embodiments of the present invention canbe any naturally occurring or synthetic steroid hormone. Naturallyoccurring corticosteroids are secreted by the adrenal cortex orgenerally the human body.

Corticosteroid molecules have the following basic structure:

Corticosteroids have been classified into four different groups (A, B,C, and D). (See e.g., Foti et al. “Contact Allergy to TopicalCorticosteroids: Update and Review on Cross-Sensitization.” RecentPatents on Inflammation & Allergy Drug Discovery 3 (2009): 33-39;Coopman et al., “Identification of cross-reaction patterns in allergiccontact dermatitis to topical corticosteroids.” Br J Dermatol 121(1989): 27-34). Class A corticosteroids are hydrocortisone types with nomodification of the D ring or C20-C21 or short chain esters on C20-C21.Main examples of Class A corticosteroids include prednisolone,hydrocortisone and methylprednisolone and their ester acetate, sodiumphosphate and succinate, cortisone, prednisone, and tixocortol pivalate.Class B corticosteroids are triamcinolone acetonide (TCA) types withcis/ketalic or diolic modifications on C16-C17. Main examples of Class Bcorticosteroids include triamcinolone acetonide (TCA), fluocinoloneacetonide, amcinonide, desonide, fluocinonide, halcinonide, budesonide,and flunisolide. Class C corticosteroids are betamethasone types with a—CH3 mutilation on C16, but no esterification on C17-C21. Main examplesof Class C corticosteroids include betamethasone, dexamethasone,desoxymethasone, fluocortolone, and halomethasone. Class Dcorticosteroids are clobetasone or hydrocortisone esterified types witha long chain on C17 and/or C21 and with no methyl group on C16. Mainexamples of Class D corticosteroids include fluticasone, clobetasonebutyrate, clobetasol propionate, hydrocortisone-17-aceponate,hydrocortisone-17-butyrate, beclomethasone dipropionate,betamethasone-17-valerate, betamethasone dipropionate,methylprednisolone aceponate, and prednicarbate.

For the present invention non-limiting examples of corticosteroids mayinclude: betamethasone, betamethasone acetate, betamethasonedipropionate, betamethasone 17-valerate, cortivazol, dexamethasone,dexamethasone acetate, dexamethasone sodium phosphate, hydrocortisone,hydrocortisone aceponate, hydrocortisone acetate, hydrocortisonebutyrate, hydrocortisone cypionate, hydrocortisone probutate,hydrocortisone sodium phosphate, hydrocortisone sodium succinate,hydrocortisone valerate, methylprednisolone, methylprednisoloneaceponate, methylprednisolone acetate, methylprednisolone sodiumsuccinate, prednisolone, prednisolone acetate, prednisolonemetasulphobenzoate, prednisolone sodium phosphate, prednisolonesteaglate, prednisolone tebutate, triamcinolone, triamcinoloneacetonide, triamcinolone acetonide 21-palmitate, triamcinolonebenetonide, triamcinolone diacetate, triamcinolone hexacetonide,alclometasone, alclometasone dipropionate, amcinonide, amelometasone,beclomethasone, beclomethasone dipropionate, beclomethasone dipropionatemonohydrate, budesonide, butixocort, butixocort propionate, ciclesonide,ciprocinonide, clobetasol, clobetasol propionate, clocortolone,clobetasone, clobetasone butyrate, clocortolone pivalate, cloprednol,cortisone, cortisone acetate, deflazacort, domoprednate, deprodone,deprodone propionate, desonide, desoximethasone, desoxycortone,desoxycortone acetate, dichlorisone, diflorasone, diflorasone diacetate,diflucortolone, difluprednate, fluclorolone, fluclorolone acetonide,fludrocortisone, fludrocortisone acetate, fludroxycortide, flumethasone,flumethasone pivalate, flunisolide, fluocinolone, fluocinoloneacetonide, fluocortin, fluocortolone, fluorometholone, fluticasone,fluticasone furoate, fluticasone propionate, fluorometholone acetate,fluoxymesterone, fluperolone, fluprednidene, fluprednidene acetate,fluprednisolone, formocortal, halcinonide, halobetasol propionate,halometasone, halopredone, halopredone acetate, hydrocortamate,isoflupredone, isoflupredone acetate, itrocinonide, loteprednoletabonate, mazipredone, meclorisone, meclorisone dibutyrate, medrysone,meprednisone, mometasone, mometasone furoate, mometasone furoatemonohydrate, nivacortol, paramethasone, paramethasone acetate,prednazoline, prednicarbate, prednisolone, prednylidene, procinonide,rofleponide, rimexolone, timobesone, tipredane, tixocortol, tixocortolpivalate and tralonide.

Embodiments of the invention include using sustained releasecorticosteroids delivered to treat pain at dosages that do not adverselysuppress the HPA axis. Such amounts delivered locally to relieve paindue to inflammation, will provide a systemic concentration that does nothave a measurable adverse effect on the HPA axis (differences if any arenot significant because any such differences are within normal assayvariability) or, as desired, may have a measurable but clinicallyinsignificant effect on the HPA axis (basal cortisol is suppressed tosome measurable extent but stress responses are adequately preserved).Further embodiments of the invention include doses during a secondperiod of time selected to adjust for a change in sensitivity of the HPAaxis to suppression following exposure during a first period of time tothe corticosteroid (FIG. 1).

Additional embodiments include doses during first and/or the secondperiod of time selected to adjust for corticosteroid-specific (orcorticosteroid- and potentially dose-specific) changes in the rate ofchange of sensitivity of the HPA axis to suppression that begin withinitial exposure. For clinically effective corticosteroids, the rate ofchange of the sensitivity of the HPA axis to exogenous corticosteroidsis both non-uniform and non-linear (FIG. 2). The rate and pattern ofchange in such sensitivity varies widely as a function of the particularcorticosteroid that is selected (FIG. 3).

Finally, it is possible to usefully characterize the change insensitivity vs. time mathematically as the (non-linear, exponential)“decay” of the sensitivity from the initial to final value, wherein thedecay parameters (Table 1) has been determined from the data furtherdescribed herein.

TABLE 1 HPA Axis Change-in-Sensitivity Decay-Parameter δ vs.Corticosteroid and Dose * Decay Parameter δ Corticosteroid (time⁻¹)Betamethasone Phosphate/Acetate (7 mg) 0.024 Triamcinolone Acetonide (40mg) 0.005 Triamcinolone Hexacetonide (20 mg) 0.070 * The inhibition ofendogenous cortisol synthesis can be related to the exogenouscorticosteroid concentration by the following equations: 1. E = (E_(max)· C^(n))/[(EC₅₀)^(n) + C^(n)) wherein E = effect, E_(max) = maximaleffect, C = concentration of exogenous corticosteroid, EC₅₀ =concentration at ½ E_(max), and n = the Hill (“shape”, or “slope”)factor; and 2. EC_(50 - final) = EC_(50 - initial) + [EC_(50 - final) −EC_(50 - initial)] · [1 − e^((−δ·time))]

Using this approach permits the determination of “δ”, the parameterdescribing the exponential decay from the initial to the final EC50.Minimization of least-squares differences was utilized to obtain thebest-fit δ.

These new findings regarding the rate and pattern of change ofsensitivity to inhibition and the lack of predictability of such ratesand patterns on the basis of, for example, steroid potency, havesignificant implications for clinically appropriate dose-selection.Those skilled in the art will appreciate the importance of a changingsensitivity to HPA axis suppression and will also appreciate both thecomplexity and counterintuitive aspects of several of these new findings(Table 1).

As a result of these clinical findings, the dose range to achieveclinically useful analgesia, with minimal or controlled modulation ofthe HPA axis, at steady state concentrations of various corticosteroidshas been determined (Table 2). In particular, it appears that the dailycorticosteroid doses at steady state concentrations, are approximately3- to 7- times greater than are predicted by prior art (Meibohm, 1999).

TABLE 2 Dose (mg/d), adjusted for individual intra-articularcorticosteroid characteristics, for expected suppression of endogenouscortisol production at steady state. Cortisol Inhibition (%)Corticosteroid 5% 10% 20% 35% 50% betamethasone (mg/d) 0.1 0.2 0.5 1.01.8 budesonide (mg/d) 0.1 0.2 0.6 1.2 2.2 des-ciclesonide (mg/d) 3.0 6.314.3 30.7 57.0 dexamethasone (mg/d) 0.1 0.2 0.4 0.9 1.6 flunisonide(mg/d) 0.3 0.5 1.2 2.6 4.8 fluticasone (mg/d) 0.1 0.1 0.3 0.6 1.1mometasone (mg/d) 0.2 0.4 0.9 2.0 3.7 methylprednisolone (mg/d) 0.3 0.71.6 3.5 6.5 prednisolone (mg/d) 0.4 0.8 1.9 4.0 7.5 triamcinoloneacetonide 0.2 0.4 0.8 1.7 3.2 (mg/d) triamcinolone hexacetonide 0.1 0.20.4 0.9 1.6 (mg/d)

TABLE 2A Total Dose Delivered (mg/month), adjusted for individualintra-articular corticosteroid characteristics, for expected suppressionof endogenous cortisol production at steady state. Cortisol Inhibition(%) Corticosteroid 5% 10% 20% 35% 50% betamethasone 3.0 6.0 15.0 30.054.0 budesonide 3.0 6.0 18.0 36.0 66.0 des-ciclesonide 90.0 189.0 429.0921.0 1710.0 dexamethasone 3.0 6.0 12.0 27.0 48.0 flunisonide 9.0 15.036.0 78.0 144.0 fluticasone 3.0 3.0 9.0 18.0 33.0 mometasone 6.0 12.027.0 60.0 111.0 methylprednisolone 9.0 21.0 48.0 105.0 195.0prednisolone 12.0 24.0 57.0 120.0 225.0 triamcinolone acetonide 6.0 12.024.0 51.0 96.0 triamcinolone hexacetonide 3.0 6.0 12.0 27.0 48.0

That higher doses of corticosteroids can be administered successfully byintra-articular injection, maximizing the likelihood of observinganti-inflammatory and analgesic responses while minimizing oreliminating adverse events from HPA axis suppression or otherwiseexcessive tissue exposure, is of profound clinical consequence forimproving the treatment of patients with arthritis.

In addition, with these continuous daily doses of intra-articularcorticosteroids, it is possible to determine the related systemic plasmalevel concentrations (Table 3) that will produce the target cortisolinhibition and not beyond, this while retaining clinically importantanti-inflammatory and analgesic activity within the joint. These plasmaconcentrations were predicted on the basis of data from short term(i.e., less than 8 days) exposure to corticosteroids. With longerexposure to corticosteroids, the “decay” (i.e., decline) of thesensitivity to corticosteroids may continue resulting in values higherthan those listed in Table 3. The levels calculated in Table 3 werepurely hypothetical calculations based on human data with immediaterelease-level doses from the literature. With sustained release dosages,more drug may be able to be delivered without seeing an increased levelof cortisol inhibition after the initial burst period. A given level ofplasma concentration may actually provide less inhibition that wouldhave been predicted or calculated using the human IR levels from theliterature.

TABLE 3 Plasma corticosteroid concentrations associated with targetlevels of cortisol inhibition at steady state. CorticosteroidConcentration in Plasma (ng/mL) associated with the Target Levels ofCortisol Inhibition (%) Corticosteroid 5% 10% 20% 35% 50% betamethasone(ng/mL) 0.33 0.70 1.57 3.38 6.27 budesonide (ng/mL) 0.60 1.27 2.85 6.1411.40 des-ciclesonide (ng/mL) 0.55 1.16 2.61 5.63 10.45 dexamethasone(ng/mL) 0.21 0.44 1.00 2.15 3.99 flunisonide (ng/mL) 0.18 0.38 0.86 1.843.42 fluticasone (ng/mL) 0.04 0.08 0.19 0.41 0.76 mometasone (ng/mL)0.15 0.32 0.71 1.54 2.85 methylprednisolone (ng/mL) 0.68 1.44 3.23 6.9612.92 prednisolone (ng/mL) 1.64 3.46 7.79 16.79 31.16 triamcinoloneacetonide (ng/mL) 0.19 0.40 0.90 1.95 3.61 triamcinolone hexacetonide(ng/mL) 0.10 0.21 0.48 1.02 1.90

The studies presented herein demonstrate for the first time thediscovery of the time-course of changes in sensitivity of the HPA axisto exogenous corticosteroids. In addition, both the mean doses and meanplasma levels shown in Tables 2 and 3 above are those after steady statehas been achieved, requiring approximately 4 to 24 days depending uponthe corticosteroid in question. The companion post-dose butpre-steady-state transients for several corticosteroids have beendescribed in FIGS. 2, 3, and 4A-4F. It is also important to note thatthe data suggest that the carefully controlled benefits from theintra-articular, sustained release of a corticosteroid of interest willpersist as long as release continues.

In one preferred embodiment, a single component sustained releaseformulation releases a dose (in mg/day) that suppresses the HPA axis byno more than between 5-40% at steady state as shown in Table 2, morepreferably no more than between 10-35% at steady state as shown in Table2. These doses are therapeutically effective without adverse sideeffects.

In another preferred embodiment, a single component sustained releaseformulation releases a dose (in mg/day) that does not measurablysuppress the HPA axis at steady state. These doses are therapeuticallyeffective without adverse side effects.

In another embodiment where both an immediate release component andsustained release component of the formulation are present, immediaterelease dose would be as shown in Table 4 and the sustained release dosewould be a dose (in mg/day) that suppresses the HPA axis by no more thanbetween 5-40% as shown in Table 2, more preferably no more than between10-35% as shown in Table 2. In addition, it is expected that sustainedrelease doses described previously will follow immediate release dosesas shown in Table 4.

TABLE 4 Immediate release relative doses (mg) Immediate Release DoseCorticosteroid (mg) betamethasone¹  5-20 budesonide²  7-28des-ciclesonide² 177-713 dexamethasone²  5-20 flunisonide² 15-60fluticasone²  3-12 mometasone² 11-44 methylprednisolone¹  40-160prednisolone¹  25-100 triamcinolone acetonide¹ 10-40 triamcinolonehexacetonide¹ 10-40 ¹clinical doses ²calculated doses

Sustained Release Delivery Platforms

The manufacture of microparticles or methods of making biodegradablepolymer microparticles are known in the art. Microparticles from any ofthe biodegradable polymers listed below can be made by, but not limitedto, spray drying, solvent evaporation, phase separation, spray drying,fluidized bed coating or combinations thereof

In certain embodiments of the invention, the microparticles are madefrom a biodegradable polymer that may include, without limitation,natural or synthetic biocompatible biodegradable materials. Naturalpolymers include, but are not limited to, proteins such as albumin,collagen, gelatin synthetic poly(aminoacids), and prolamines;glycosaminoglycans, such as hyaluronic acid and heparin;polysaccharides, such as alginates, chitosan, starch, and dextrans; andother naturally occurring or chemically modified biodegradable polymers.Synthetic biocompatible biodegradable materials include, but are notlimited to the group comprising of, poly(lactide-co-glycolide) (PLGA),polylactide (PLA), polyglycolide (PG), polyhydroxybutyric acid,poly(trimethylene carbonate), polycaprolactone (PCL), polyvalerolactone,poly(alpha-hydroxy acids), poly(lactones), poly(amino-acids),poly(anhydrides), polyketals poly(arylates), poly(orthoesters),poly(orthocarbonates), poly(phosphoesters), poly(ester-co-amide),poly(lactide-co-urethane, polyethylene glycol (PEG), polyvinyl alcohol(PVA), PVA-g-PLGA, PEGT-PBT copolymer(polyactive), polyurethanes,polythioesters, methacrylates, poly(N-isopropylacrylamide), PEO-PPO-PEO(pluronics), PEO-PPO-PAA copolymers, and PLGA-PEO-PLGA blends andcopolymers thereof, multi-block polymer configurations such asPLGA-PEG-PLGA, and any combinations thereof. These polymers may be usedin making controlled release or sustained release compositions disclosedherein.

In a preferred embodiment, the microparticles are formed frompoly(d,1-lactic-co-glycolic acid) (PLGA), which is commerciallyavailable from a number of sources. Biodegradable PLGA copolymers areavailable in a wide range of molecular weights and ratios of lactic toglycolic acid. If not purchased from a supplier, then the biodegradablePLGA copolymers may be prepared by the procedure set forth in U.S. Pat.No. 4,293,539 (Ludwig, et al.), the disclosure of which is herebyincorporated by reference in its entirety. Ludwig prepares suchcopolymers by condensation of lactic acid and glycolic acid in thepresence of a readily removable polymerization catalyst (e.g., a strongacid ion-exchange resin such as Dowex HCR-W2-H). However, any suitablemethod known in the art of making the polymer can be used.

In the coacervation process, a suitable biodegradable polymer isdissolved in an organic solvent. Suitable organic solvents for thepolymeric materials include, but are not limited to acetone, halogenatedhydrocarbons such as chloroform and methylene chloride, aromatichydrocarbons such as toluene, halogenated aromatic hydrocarbons such aschlorobenzene, and cyclic ethers such as dioxane. The organic solventcontaining a suitable biodegradable polymer is then mixed with anon-solvent such as silicone based solvent. By mixing the misciblenon-solvent in the organic solvent, the polymer precipitates out ofsolution in the form of liquid droplets. The liquid droplets are thenmixed with another non-solvent, such as heptane or petroleum ether, toform the hardened microparticles. The microparticles are then collectedand dried. Process parameters such as solvent and non-solventselections, polymer/solvent ratio, temperatures, stirring speed anddrying cycles are adjusted to achieve the desired particle size, surfacesmoothness, and narrow particle size distribution.

In the phase separation or phase inversion procedures entrap dispersedagents in the polymer to prepare microparticles. Phase separation issimilar to coacervation of a biodegradable polymer. By addition of anonsolvent such as petroleum ether, to the organic solvent containing asuitable biodegradable polymer, the polymer is precipitates from theorganic solvent to form microparticles.

In the salting out process, a suitable biodegradable polymer isdissolved in an aqueous miscible organic solvent. Suitable watermiscible organic solvents for the polymeric materials include, but arenot limited to acetone, as acetone, acetonitrile, and tetrahydrofuran.The water miscible organic solvent containing a suitable biodegradablepolymer is then mixed with an aqueous solution containing salt. Suitablesalts include, but are not limited to electrolytes such as magnesiumchloride, calcium chloride, or magnesium acetate and non-electrolytessuch as sucrose. The polymer precipitates from the organic solvent toform microparticles, which are collected and dried. Process parameterssuch as solvent and salt selection, polymer/solvent ratio, temperatures,stirring speed and drying cycles are adjusted to achieve the desiredparticle size, surface smoothness, and narrow particle sizedistribution.

Alternatively, the microparticles may be prepared by the process ofRamstack et al., 1995, described in published international patentapplication WO 95/13799, the disclosure of which is incorporated hereinin its entirety. The Ramstack et al. process essentially provides for afirst phase, including an active agent and a polymer, and a secondphase, that are pumped through a static mixer into a quench liquid toform microparticles containing the active agent. The first and secondphases can optionally be substantially immiscible and the second phaseis preferably free from solvents for the polymer and the active agentand includes an aqueous solution of an emulsifier.

In the spray drying process, a suitable biodegradable polymer isdissolved in an organic solvent and then sprayed through nozzles into adrying environment provided with sufficient elevated temperature and/orflowing air to effectively extract the solvent. Adding surfactants, suchas sodium lauryl sulfate can improve the surface smoothness of themicroparticles.

Alternatively, a suitable biodegradable polymer can be dissolved ordispersed in supercritical fluid, such as carbon dioxide. The polymer iseither dissolved in a suitable organic solvent, such as methylenechloride, prior to mixing in a suitable supercritical fluid or directlymixed in the supercritical fluid and then sprayed through a nozzle.Process parameters such as spray rate, nozzle diameter, polymer/solventratio, and temperatures, are adjusted to achieve the desired particlesize, surface smoothness, and narrow particle size distribution.

In a fluidized bed coating, the drug is dissolved in an organic solventalong with the polymer. The solution is then processed, e.g., through aWurster air suspension coating apparatus to form the final microcapsuleproduct.

The microparticles can be prepared in a size distribution range suitablefor local infiltration or injection. The diameter and shape of themicroparticles can be manipulated to modify the release characteristics.In addition, other particle shapes, such as, for example, cylindricalshapes, can also modify release rates of a sustained releasecorticosteroid by virtue of the increased ratio of surface area to massinherent to such alternative geometrical shapes, relative to a sphericalshape. The microparticles have a mass mean diameter ranging betweenabout 0.5 to 500 microns. In a preferred embodiment, the microparticleshave a mass mean diameter of between 10 to about 100 microns.

Biodegradable polymer microparticles that deliver sustained releasecorticosteroids may be suspended in suitable aqueous or non-aqueouscarriers which may include, but is not limited to water, saline,pharmaceutically acceptable oils, low melting waxes, fats, lipids,liposomes and any other pharmaceutically acceptable substance that islipophilic, substantially insoluble in water, and is biodegradableand/or eliminatable by natural processes of a patient's body. Oils ofplants such as vegetables and seeds are included. Examples include oilsmade from corn, sesame, cannoli, soybean, castor, peanut, olive,arachis, maize, almond, flax, safflower, sunflower, rape, coconut, palm,babassu, and cottonseed oil; waxes such as carnoba wax, beeswax, andtallow; fats such as triglycerides, lipids such as fatty acids andesters, and liposomes such as red cell ghosts and phospholipid layers.

Corticosteroid Loading of and Release from Biodegradable PolymerMicroparticles

When an intra-articularly delivered corticosteroid is incorporated intoa biodegradable polymer for sustained release into a joint at a dosagethat does not suppress the HPA axis, preferred loadings of saidcorticosteroid are from about 5% to about 40% (w/w) of the polymer,preferably about 5% to about 30%, more preferably about 5% to about 28%of the polymer.

As the biodegradable polymers undergo gradual bio-erosion within thejoint, the corticosteroid is released to the inflammatory site. Thepharmacokinetic release profile of the corticosteroid by thebiodegradable polymer may be first order, zero order, bi- ormulti-phasic, to provide desired treatment of inflammatory related pain.In any pharmacokinetic event, the bio-erosion of the polymer andsubsequent release of the corticosteroid may result in a controlledrelease of a corticosteroid from the polymer matrix. The rate of releaseat dosages that do not suppress the HPA axis are described above.

Excipients

The release rate of the corticosteroid from a biodegradable polymermatrix can be modulated or stabilized by adding a pharmaceuticallyacceptable excipient to the formulation. An excipient may include anyuseful ingredient added to the biodegradable polymer depot that is not acorticosteroid or a biodegradable polymer. Pharmaceutically acceptableexcipients may include without limitation lactose, dextrose, sucrose,sorbitol, mannitol, starches, gum acacia, calcium phosphate, alginates,tragacanth, gelatin, calcium silicate, microcrystalline cellulose, PEG,polysorbate 20, polysorbate 80, polyvinylpyrrolidone, cellulose, water,saline, syrup, methyl cellulose, and carboxymethyl cellulose. Anexcipient for modulating the release rate of a corticosteroid from thebiodegradable drug depot may also include without limitation poreformers, pH modifiers, reducing agents, antioxidants, and free radicalscavengers.

Delivery of Corticosteroid Microparticles

Parenteral administration of formulations of the invention can beeffected by intra-articular injection or other injection using a needle.To inject the microparticles into a joint, needles having a gauge ofabout 14-28 gauge are suitable. It will be appreciated by those skilledin the art that formulations of the present invention may be deliveredto a treatment site by other conventional methods, including catheters,infusion pumps, pens devices, injection guns and the like.

All references, patents, patent applications or other documents citedare hereby incorporated by reference.

EXAMPLES

The present invention is further defined in the following Examples. Itshould be understood that these Examples, while indicating preferredembodiments of the invention, are given by way of illustration only.From the above discussion and these Examples, one skilled in the art canascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various uses andconditions.

Example 1 Sustained-Release Betamethasone or Triamcinolone AcetonideMicroparticles

In one embodiment, the microparticle formulation contains a copolymer ofDL-lactide (or L-lactide) and glycolide in a 45:55 molar ratio (up to75:25 molar ratio) with an inherent viscosity ranging from 0.15 to 0.60dL/g with either an ester or acid end group plus either thecorticosteroid betamethasone or triamcinolone acetonide. Ifbetamethasone is used, then the betamethasone is in the form of eitherbetamethasone acetate, betamethasone diproprionate or a combinationthereof. The total amount of betamethasone or triamcinolone acetonideincorporated into the microparticle ranges from 10% to 30% (w/w). Themicroparticles are formulated to mean mass range in size from 10 to 100microns. The population of microparticles is formulated to be deliveredthrough a 19 gauge or higher needle. Additional excipients may be addedsuch as, but not limited to, carboxymethylcellulose sodium, mannitol,polysorbate-80, sodium phosphate, sodium chloride, polyethylene glycolto achieve isotonicity and promote syringeability. If betamethasone isused, then the betamethasone incorporated into the microparticlepopulation provides an initial release (burst) of about 5-20 mg of drugover a period of 1 to 12 hours, followed by a steady state release ofdrug at a rate of about 0.1 to 1.0 mg/day over a period of 14 to 90days. If triamcinolone acetonide is used, then the drug incorporatedinto the microparticle population provides an initial release (burst) ofabout 10-40 mg of drug over a period of 1 to 12 hours, followed by asteady state release of drug at a rate of about 0.2 to 1.7 mg/day over aperiod of 14 to 90 days.

Example 2

Sustained-Release Betamethasone or Triamcinolone AcetonideMicroparticles with an Immediate Release Form

In another embodiment, the microparticle formulation of Example 1 isfurther admixed with an immediate release betamethasone or triamcinoloneacetonide component, such as a betamethasone or triamcinolone acetonidecontaining solution. If betamethasone is used, then the betamethasone inthe immediate release component is in the form of either betamethasoneacetate, betamethasone diproprionate or a combination thereof. Ifbetamethasone is used, then the immediate release component provides aninitial release of a total of about 5 to 20 mg of betamethasone over thefirst 1-10 days, while the sustained release component releasesbetamethasone at a rate of about 0.1 to 1.0 mg/day over the first 14 to90 days following administration. If triamcinolone acetonide is used,then the immediate release component provides an initial release of atotal of 10 to 40 mg of drug over the first 1-10 days, while thesustained release component releases drug at a rate of about 0.2 to 1.7mg/day over the first 14 to 90 days following administration.

Example 3 Determination of Time-Variance in HPA Axis Sensitivity

Adult volunteers (N=4 to 9 per group) give appropriate informed consent.Each individual in each group receives a single intra-articularadministration of an exogenous corticosteroid (triamcinolone acetonide40 mg; triamcinolone hexacetonide 20; betamethasone 7 mg (disodiumphosphate 4 mg/acetate 3 mg). Blood samples for measurement ofcorticosteroid concentrations and/or cortisol concentrations are drawnat 8 AM at baseline and on days 1, 7, 9, 10, 12, 14, 18, and 21. Theextent of suppression of endogenous cortisol was measured in eachsubject in each group. The extent of cortisol suppression predicted bypreviously published models (Meibohm, 1999) was determined and comparedto observations (FIGS. 4A, 4C, and 4E). The change (decrease) in HPAaxis sensitivity vs. time is then determined on a day-by-day and finalbasis (FIGS. 4B, 4D, and 4F), permitting determination of the correctsteady-state intra-articular doses of corticosteroid to achieve, orlimit, HPA axis suppression to the desired level.

Example 4 Preparation of Triamcinolone Acetonide Microparticles bySpinning Disk

A pharmaceutical depot was prepared comprised of the corticosteroid,triamcinolone acetonide (TCA,9α-Fluoro-11β,16α,17α,21-tetrahydroxy-1,4-pregnadiene-3,20-dione16,17-acetonide; 9α-Fluoro-16α-hydroxyprednisolone 16α,17α-acetonide)incorporated into PLGA microparticles.

In one suitable thirty day formulation, 250 mg of triamcinoloneacetonide and 750 mg of PLGA (lactide: glycolide molar ratio of 75:25,inherent viscosity of 0.4 dL/g and molecular weight of 54 kDa) weredispersed in 14.25 grams of dichloromethane. The dispersion was atomizedinto micro-droplets by adding the dispersion to the feed well of arotating disk, rotating at a speed of approximately 3300 rpm inside atemperature controlled chamber maintained at 38-45° C. The solvent wasevaporated to produce solid microparticles. The microparticles werecollected using a cyclone separator and, subsequently, sieved through a150 μm sieve.

Particle size of the TCA incorporated microparticles was determinedusing laser diffraction (Malvern Mastersizer 2000) by dispersing a 250mg aliquot in water, with the refractive index (RI) for water and PLGA,set at 1.33 and 1.46 respectively. Sonication was maintained as thesample was stirred at 2500 rpm and measurements taken every 15 seconds,with the average of three measurements reported. 10 mg of TCA containingmicroparticles were added to 10 mL of dimethylsulfoxide (DMSO), mixeduntil dissolved and an aliquot analyzed by HPLC to determine themicroparticle drug load. Another 4 mg of TCA containing microparticleswere suspended in 20 mL of phosphate buffered saline (PBS) containing0.5% sodium dodecyl sulfate (SDS) maintained at 37° C. 0.5 mL of themedia was removed at regular intervals, replaced at each interval withan equivalent amount of fresh media to maintain a constant volume, andanalyzed by HPLC to determine microparticle in vitro release. Analysisby HPLC was conducted using a C18 (Waters Nova-Pack C-18, 3.9×150 mm)and 35% acetonitrile mobile phase at 1 ml/min flow rate with UVdetection at 240 nm. The results are shown in Table 5.

TABLE 5 Analytical Results for 25% Triamcinolone Acetonide PLGA 75:25Microparticles PLGA (lactide: glycolide molar ratio ratio/ inherent DrugIn- viscosity/ load corpo- molecular (% ration weight/ TCA effi-Particle In vitro target % by ciency size release TCA weight) (%) (Dv,μm ) (%) 75:25 24 96 D0.1: 32 μm 0.2 day: 5.1 carboxylic D0.5: 49 μm 1day: 13.5 acid D0.9: 73 μm 3 day: 29.6 end-capped 7 day: 52.6 0.4 dL/g14 day 70.9 54 kDa 21 day: 76.4 25% 28 day: 79.1

The in vitro cumulative release profile is graphed in FIG. 5.

In one iteration of these data, the amount of TCA released per day wascalculated based on a human dose, as exemplified in Table 2, that wouldachieve a transient suppression of endogenous cortisol (greater than50%) and, within 14 days, achieve cortisol suppression of endogenouscortisol of less than 35% as shown in FIG. 6. In a second iteration ofthese data, the amount of triamcinolone acetonide released per day wascalculated based on a human dose, as exemplified in Table 2 that wouldnot suppress the HPA axis, i.e. endogenous cortisol suppression neverexceeding 35% as shown in FIG. 7. These calculated doses equal 376 mg ofmicroparticles containing 94 mg of TCA and 80 mg of microparticlescontaining 20 mg of TCA, respectively.

In a second preparation of the same formulation, analyzed and in vitrorelease plotted in the same manner, the results are equivalent as shownin Table 6, and FIGS. 8, 9 and 10. The calculated human dose, asexemplified in Table 2 that would achieve a transient suppression ofendogenous cortisol (greater than 50%) and, within 14 days, achievecortisol suppression of endogenous cortisol of less than 35% equals 280mg of microparticles containing 70 mg of TCA. The calculated human dose,as exemplified in Table 2 that would not suppress the HPA axis, i.e.endogenous cortisol suppression never exceeding 35% equals 68 mg ofmicroparticles containing 17 mg of TCA.

TABLE 6 Analytical Results for Alternate Preparation of a Nominal 25%Triamcinolone Acetonide PLGA 75:25 Microparticles PLGA (lactide:glycolide molar ratio ratio/ inherent Drug In- viscosity/ load corpo-molecular (% ration weight/ TCA effi- Particle In vitro target % byciency size release TCA weight) (%) (Dv, μm ) (%) 75:25 27.5 110 D0.1:30.9 μm 0.2 day: 4.8 carboxylic D0.5: 48.2 μm 1 day: 15 acid D0.9: 71.0μm 3 day: 28.5 end-capped 7 day: 50.2 0.4 dL/g 14 day 67.1 54 kDa 21day: 74.2 25% 28 day: 75.7

Influence of PEG on PLGA 75:25 Formulations:

In other suitable formulations, polyethylene glycol was added to thePLGA 75:25 polymers while keeping the target amount of triamcinoloneacetonide constant. PEG/PLGA blends are known to allow for more completeand faster release of pharmaceutical agents incorporated intomicroparticles than PLGA alone (Cleek et al. “Microparticles ofpoly(DL-lactic-coglycolic acid)/poly(ethylene glycol) blends forcontrolled drug delivery.” J Control Release 48 (1997): 259-268;Morlock, et al. “Erythropoietin loaded microspheres prepared frombiodegradable LPLG-PEO-LPLG triblock copolymers: protein stabilizationand in-vitro release properties.” J Control Release, 56 (1-3) (1998):105-15; Yeh, “The stability of insulin in biodegradable microparticlesbased on blends of lactide polymers and polyethylene glycol.” JMicroencapsul, 17(6) (2000): 743-56).

In one iteration, 250 mg of triamcinolone acetonide, 50 mg ofpolyethylene glycol (PEG 1450) and 700 mg of PLGA (lactide: glycolidemolar ratio of 75:25, inherent viscosity of 0.4 dL/g and molecularweight of 54 kDa) were dispersed in 14 grams of dichloromethane. Inanother iteration, 250 mg of triamcinolone acetonide, 100 mg ofpolyethylene glycol (PEG 3350) and 650 mg of PLGA (lactide: glycolidemolar ratio of 75:25, inherent viscosity of 0.4 dL/g and molecularweight of 54 kDa) were dispersed in 13 grams of dichloromethane. Thedispersions were atomized into micro-droplets by adding the dispersionto the feed well of a rotating disk, rotating at a speed ofapproximately 3300 rpm inside a temperature controlled chambermaintained at 38-45° C. The solvent was evaporated to produce solidmicroparticles. The microparticles were collected using a cycloneseparator and, subsequently, sieved through a 150 μm sieve.

The microparticles were analyzed as described above and the data isshown in Table 7.

TABLE 7 Analytical Results of Nominal 25% Triamcinolone Acetonide PLGA75:25 Microparticles containing Polyethylene Glycol (PEG) Additive PLGA(lactide: glycolide molar ratio ratio/ inherent viscosity/ molecularDrug Incor- weight/ load poration target % (% effi- In vitro TCA/ TCA byciency Particle size release % PEG weight) (%) (Dv, μm ) (%) 75:25 29.4118 D0.1: 36.2 μm 0.2 day: 3.6 carboxylic D0.5: 59.0 μm 1 day: 13.8 acidD0.9: 95.5 μm 3 day: 30.1 end-capped 7 day: 49.5 0.4 dL/g 14 day 65.5 54kDa 21 day: 74.0 25% 28 day: 78.5 5% PEG 1450 75:25 24.5 98 D0.1: 32.0μm 0.2 day: 4.1 carboxylic D0.5: 52.4 μm 1 day: 11.7 acid D0.9: 79.0 μm3 day: 24.5 end-capped 7 day: 40.8 0.4 dL/g 14 day: 55.8 54 kDa 21 day:63.7 25% 28 day: 69.5 10% PEG 3350

The in vitro cumulative release profile is graphed in FIG. 11 and FIG.12. PEG did not seem to enhance the release of the TCA in eitherformulation, as would be expected. In fact, at higher percentages ofPEG, albeit a different molecular weight (higher percentages of PEG 1350were unmanageable due to the agglomeration of microparticles), therelease rate was slower.

In one iteration of these in vitro release data, the amount of TCAreleased per day was calculated based on a human dose, as exemplified inTable 2, that would achieve a temporary suppression of endogenouscortisol (greater than 50%) and, within 14 days, achieve cortisolsuppression of endogenous cortisol of less than 35% as shown in FIG. 13and FIG. 14. These calculated doses equal 296 mg of microparticlescontaining 74 mg of TCA and 316 mg of microparticles containing 79 mg ofTCA, respectively. In a second iteration of these data, the amount oftriamcinolone acetonide released per day was calculated based on a humandose, as exemplified in Table 2 that would not suppress the HPA axis,i.e. endogenous cortisol suppression never exceeding 35% as shown inFIGS. 15 and 16. These calculated doses equal 68 mg of microparticlescontaining 17 mg of TCA and 88 mg of microparticles containing 22 mg ofTCA, respectively.

Other TCA containing formulations were tried with PEG and PLGA 75:25without success. A PLGA microparticle formulation containing 25% TCA and25% PEG 1450 agglomerated during manufacture and storage. Another PLGAformulation containing 40% TCA and 15% PEG 1450 gave similar results tothe microparticles containing 40% TCA and no PEG.

Influence of Triamcinolone Acetonide Content in PLGA 75:25Microparticles:

Triamcinolone acetonide containing microparticle depots were preparedand analyzed, as described above, with the exception of using 100 mg,150 mg, 200 mg and 400 mg triamcinolone acetonide and adding to a 5%PLGA dichloromethane solution. The physical characteristics of theseformulations are shown in Table 8.

TABLE 8 Analytical Results of PLGA 75:25 Microparticles containingvarying amounts of Triamcinolone Acetonide PLGA (lactide: glycolidemolar ratio ratio/ inherent Drug viscosity/ load Incor- molecular (%poration weight/ TCA effi- In vitro target % by ciency Particle sizerelease TCA weight) (%) (Dv, μm) (%) 75:25 43.4 109 D0.1: 40.7 μm 0.2day: 6.6 carboxylic D0.5: 70.7 μm 1 day: 24.2 acid D0.9: 167 μm 3 day:53.8 end-capped 7 day: 82.5 0.4 dL/g 14 day 89.4 54 kDa 21 day: 89.6 40%28 day: 87.5 75:25 20.2 101 D0.1: 28.7 μm 0.2 day: 5.3 carboxylic D0.5:45.2 μm 1 day: 13.5 acid D0.9: 70.5 μm 3 day: 23.7 end-capped 7 day:35.3 0.4 dL/g 14 day 44.4 54 kDa 21 day: 48.1 20% 28 day: 50.6 75:2515.9 106 D0.1: 30.7 μm 0.2 day: 3.9 carboxylic D0.5: 47.8 μm 1 day: 9.0acid D0.9: 74.8 μm 3 day: 14.2 end-capped 7 day: 19.3 0.4 dL/g 14 day22.7 54 kDa 21 day: 24.6 15% 28 day: 27.6 75:25 11.7 117 D0.1: 31.0 μm0.2 day: 2.3 carboxylic D0.5: 57.9 μm 1 day: 4.4 acid D0.9: 118 μm 3day: 5.9 end-capped 7 day: 7.5 0.4 dL/g 14 day 9.9 54 kDa 21 day: 11.710% 28 day: 15.8

The in vitro cumulative release profiles for these four other TCAcontaining PLGA 75:25 microparticle depots are graphed in FIG. 17, alongwith the preferred formulation (25% TCA). The tabulated data and graphshow the impact of the percent TCA incorporated in the PLGAmicroparticles on the in vitro release profile. The 10%, 15% and 20% TCAcontaining PLGA microparticles exhibit a slower release profile, with asignificant less cumulative release over 28 days, less than 20%, 30% and55% respectively, than the 25% TCA PLGA depot exemplified in Example 4.The 40% TCA containing depot exhibits a faster release profile, withgreater than 80% of the triamcinolone released by day 7 with a similartotal cumulative release, than the 25% TCA PLGA depot exemplified inExample 4.

Influence of Molecular Weight on TCA PLGA 75:25 MicroparticleFormulations:

In another microparticle formulation, triamcinolone acetonide wasincorporated in PLGA of the same lactide to glycolide molar ratio ascited in Example 4 but of a lower molecular weight. Low molecular weightPLGA is known to allow for more complete and faster release ofpharmaceutical agents incorporated into microparticles than their highermolecular weight counterparts. (Anderson et al. “Biodegradation andbiocompatibility of PLA and PLGA microspheres.” Advanced Drug DeliveryReviews 28 (1997): 5-24; Bouissou et al., “Poly(lactic-co-glycolicacid)Microspheres.” Polymer in Drug Delivery (2006): Chapter 7).

250 mg of triamcinolone acetonide and 750 mg of PLGA (lactide: glycolidemolar ratio of 75:25, inherent viscosity of 0.27 dL/g and molecularweight of 29 kDa) were dispersed in 14.25 grams of dichloromethane. Thedispersion was atomized into micro-droplets by adding the dispersion tothe feed well of a rotating disk, rotating at a speed of approximately3300 rpm inside a temperature controlled chamber maintained at 38-45° C.The solvent was evaporated to produce solid microparticles. Themicroparticles were collected using a cyclone separator and,subsequently, sieved through a 150 μm sieve.

Particle size of the TCA incorporated microparticles was determinedusing laser diffraction (Malvern Mastersizer 2000) by dispersing a 250mg aliquot in water, with the refractive index (RI) for water and PLGA,set at 1.33 and 1.46 respectively. Sonication was maintained as thesample was stirred at 2500 rpm and measurements taken every 15 seconds,with the average of three measurements reported. 10 mg of TCA containingmicroparticles were added to 10 mL of dimethylsulfoxide (DMSO), mixeduntil dissolved and an aliquot analyzed by HPLC to determine themicroparticle drug load. Another 4 mg of TCA containing microparticleswere suspended in 20 mL of phosphate buffered saline (PBS) containing0.5% sodium dodecyl sulfate (SDS) maintained at 37° C. 0.5 mL of themedia was removed at regular intervals, replaced at each interval withan equivalent amount of fresh media to maintain a constant volume, andanalyzed by HPLC to determine microparticle in vitro release. Analysisby HPLC was conducted using a C18 (Waters Nova-Pack C-18, 3.9×150 mm)and 35% acetonitrile mobile phase at 1 ml/min flow rate with UVdetection at 240 nm. The results are shown in Table 9.

TABLE 9 Analytical Results of a Nominal 25% Triamcinolone Acetonide PLGA75:25 (29 kDa) Microparticles PLGA (lactide: glycolide molar ratioratio/ inherent viscosity/ molecular Drug Incor- weight/ load porationtarget % (% effi- In vitro TCA/ TCA by ciency Particle size release %PEG weight) (%) (Dv, μm ) (%) 75:25 29.4 118 D0.1: 34.1 μm 0.2 day: 4.0carboxylic D0.5: 56.5 μm 1 day: 11.3 acid D0.9: 95.2 μm 3 day: 22.5end-capped 7 day: 35.9 0.27 dL/g 14 day: 48.3 29 kDa 21 day: 53.4 25% 28day: 56.5

In vitro cumulative release data is graphed in FIG. 18, along with thepreferred formulation using a higher molecular PLGA 75:25. The use oflower molecular weight PLGA (29 kDa) did not improve the release of thetriamcinolone acetonide from the microparticles as expected, in fact therate of release decreased and the release was incomplete as compared tohigher molecular weight PLGA (PLGA, 54 kDa).

In another formulation of low molecular weight PLGA 75:25(29 kDa),polyethylene glycol, 10% PEG 3350, was added while maintaining the sameamount of triamcinolone acetonide. As shown with other PEG containingformulations, there was no impact of this additive on the cumulativepercent in vitro release profile as compared to the formulation notcontaining PEG (data not shown).

Influence of PLGA Lactide to Glycolide Ratio:

In other triamcinolone acetonide microparticle formulations, PLGA ofequimolar lactide to glycolide ratio were employed instead of PLGA(75:25). PLGA (50:50) is known to allow for faster degradation andrelease of pharmaceutical agents incorporated into microparticles thanPLGA's with greater lactide versus glycolide content (Anderson et al.“Biodegradation and biocompatibility of PLA and PLGA microspheres.”Advanced Drug Delivery Reviews 28 (1997): 5-24; Bouissou et al.,“Poly(lactic-co-glycolicacid) Microspheres.” Polymer in Drug Delivery(2006): Chapter 7). Multiple formulations using PLGA 50:50 withdiffering amounts of triamcinolone acetonide, with and without PEG,different PLGA molecular weights and different PLGA endcaps wereexemplified.

Formulations were prepared with 200 mg, 250 mg, 300 mg and 350 mg oftriamcinolone acetonide and corresponding amount of PLGA (lactide:glycolide molar ratio of 50:50, inherent viscosity of 0.48 dL/g andmolecular weight of 66 kDa) to yield 1000 mg total solids were dispersedinto a quantity of dichloromethane to a achieve a 5% PLGA solution. Inanother iteration, 300 mg of triamcinolone acetonide, 100 mg ofpolyethylene glycol (PEG 3350) and 650 mg of PLGA (lactide: glycolidemolar ratio of 50:50, inherent viscosity of 0.48 dL/g and molecularweight of 66 kDa) were dispersed in 14.25 grams of dichloromethane. Inanother iteration, 300 mg of triamcinolone acetonide and 700 mg of PLGA(lactide: glycolide molar ratio of 50:50, inherent viscosity of 0.18dL/g and molecular weight of 18 kDa) to yield 1000 mg total solids weredispersed in 14.25 grams of dichloromethane. The dispersions wereatomized into micro-droplets by adding the dispersion to the feed wellof a rotating disk, rotating at a speed of approximately 3300 rpm insidea temperature controlled chamber maintained at 38-45° C. The solvent wasevaporated to produce solid microparticles. The microparticles werecollected using a cyclone separator and, subsequently, sieved through a150 μm sieve.

Particle size of the TCA incorporated microparticles was determinedusing laser diffraction (Malvern Mastersizer 2000) by dispersing a 250mg aliquot in water, with the refractive index (RI) for water and PLGA,set at 1.33 and 1.46 respectively. Sonication was maintained as thesample was stirred at 2500 rpm and measurements taken every 15 seconds,with the average of three measurements reported. 10 mg of TCA containingmicroparticles were added to 10 mL of dimethylsulfoxide (DMSO), mixeduntil dissolved and an aliquot analyzed by HPLC to determine themicroparticle drug load. Another 4 mg of TCA containing microparticleswere suspended in 20 mL of phosphate buffered saline (PBS) containing0.5% sodium dodecyl sulfate (SDS) maintained at 37° C. 0.5 mL of themedia was removed at regular intervals, replaced at each interval withan equivalent amount of fresh media to maintain a constant volume, andanalyzed by HPLC to determine microparticle in vitro release. Analysisby HPLC was conducted using a C18 (Waters Nova-Pack C-18, 3.9×150 mm)and 35% acetonitrile mobile phase at 1 ml/min flow rate with UVdetection at 240 nm. The results are shown in Table 10.

TABLE 10 Analytical Results of Triamcinolone Acetonide PLGA 50:50Microparticle Formulations PLGA (lactide: glycolide molar ratio ratio/inherent viscosity/ Drug molecular load Incor- weight/ (% porationtarget % TCA effi- In vitro TCA/ by ciency Particle size release % PEGweight) (%) (Dv, μm ) (%) 50:50 19.2 96 D0.1: 30.0 μm 0.2 day: 2.1carboxylic D0.5: 48.5 μm 1 day: 3.3 acid D0.9: 77.0 μm 3 day: 17.0end-capped 7 day: 18.7 0.48 dL/g 14 day: 21.0 66 kDa 21 day: 23.5 20%TCA 28 day: 25.6 50:50 23.9 95.6 D0.1: 30.2 μm 0.2 day: 4.0 carboxylicD0.5: 48.2 μm 1 day: 7.8 acid D0.9: 75.8 μm 3 day: 21.1 end-capped 7day: 32.1 0.48 dL/g 14 day: 39.2 66 kDa 21 day: 40.0 25% TCA 28 day:40.8 50:50 29.3 97.6 D0.1: 31.5 μm 0.2 day: 5.1 carboxylic D0.5: 48.0 μm1 day: 16.0 acid D0.9: 68.9 μm 3 day: 33.6 end-capped 7 day: 49.9 0.48dL/g 14 day: 54.0 66 kDa 21 day: 53.2 30% TCA 28 day: 52.2 50:50 27.2 91D0.1: 37.6 μm 0.2 day: 4.4 carboxylic D0.5: 59.8 μm 1 day: 9.8 acidD0.9: 93.9 μm 3 day: 13.8 end-capped 7 day: 17.7 0.18 dL/g 14 day: 21.918 kDa 21 day: 26.3 30% TCA 28 day: 36.6 50:50 30.4 101 D0.1: 38.1 μm0.2 day: 4.2 carboxylic D0.5: 56.6 μm 1 day: 14.6 acid D0.9: 82.1 μm 3day: 32.2 end-capped 7 day: 51.0 0.48 dL/g 14 day: 60.1 66 kDa 21 day:61.1 30% TCA 28 day: 60.1 10% PEG 3350 50:50 34.4 98.3 D0.1: 35.1 μm 0.2day: 7.1 carboxylic D0.5: 52.3 μm 1 day: 23.3 acid D0.9: 75.6 μm 3 day:47.6 end-capped 7 day: 66.9 0.48 dL/g 14 day: 69.3 66 kDa 21 day: 68.335% TCA 28 day: 66.7 50:50 ester 23.2 93 D0.1: 34.2 μm 0.2 day: 3.1endcapped D0.5: 51.7 μm 1 day: 7.8 0.4 dL/g D0.9: 77.4 μm 3 day: 12.5 66kDa 7 day: 15.4 25% TCA 14 day: 16.2 21 day: 16.0 28 day: 16.4

In-vitro release profiles of the various PLGA (50:50) formulations areshown in the FIG. 19. The use of PLGA (50:50) did not improve therelease kinetics of the triamcinolone acetonide as compared to the PLGA(75:25). Unexpectedly, 25% triamcinolone acetonide microparticles inPLGA (50:50) release the corticosteroid at a slower rate and give anincomplete release as compared to the equivalent amount of triamcinoloneacetonide incorporated in PLGA 75:25. All the PLGA 50:50 formulationshow a substantial lag phase, where little or any TCA is being releasedafter 7 days, which continues to about day 50. As observed with TCA PLGA75:25 formulations, increasing the amount of TCA increases the rate ofrelease and allows for more TCA to be released before entering the lagphase. Similarly, the addition of PEG has minimal influence on therelease rate of TCA, while lower molecular weight PLGA 50:50 decreasethe release rate as observed with PLGA 75:25 formulations.

Based on the studies described herein, the Class B corticosteroidmicroparticle formulations, for example, the TCA microparticleformulations, exhibiting the desired release kinetics have the followingcharacteristics: (i) the corticosteroid is between 22%-28% of themicroparticle; and (ii) the polymer is PLGA having a molecular weight inthe range of about 40 to 70 kDa, having an inherent viscosity in therange of 0.3 to 0.5 dL/g, and or having a lactide:glycolide molar ratioof 80:20 to 60:40.

Example 5 Preparation of Triamcinolone Acetonide PLGA Microparticles bySolid in Oil in Water (S/O/W) Emulsion

A pharmaceutical depot was prepared comprised of the corticosteroid,triamcinolone acetonide (TCA,9α-Fluoro-11β,16α,17α,21-tetrahydroxy-1,4-pregnadiene-3,20-dione16,17-acetonide; 9α-Fluoro-16α-hydroxyprednisolone 16α,17α-acetonide)incorporated into microparticles.

Formulations were prepared by dissolving approximately 1 gram of PLGA in6.67 mL of dichloromethane (DCM). To the polymer solution, 400 mg oftriamcinolone acetonide was added and sonicated. Subsequently, thecorticosteroid containing dispersion was poured into 200 mL of 0.3%polyvinyl alcohol (PVA) solution while homogenizing with a Silversonhomogenizer using a rotor fixed with a Silverson Square Hole High ShearScreenTM, set to rotate at approximately 2,000 rpm to form themicroparticles. After two minutes, the beaker was removed, and a glassmagnetic stirrer) added to the beaker, which was then placed onto amulti-way magnetic stirrer and stirred for four hours at 300 rpm toevaporate the DCM. The microparticles were then washed with 2 liters ofdistilled water, sieved through a 100 micron screen. The microparticleswere then lyophilized for greater than 96 hours and vacuum packed.

Particle size of the TCA incorporated microparticles was determinedusing laser diffraction (Beckman Coulter LS 230) by dispersing a 50 mgaliquot in water, with the refractive index (RI) for water and PLGA, setat 1.33 and 1.46 respectively. The sample was stirred at the particlesize measurement measurements taken and the results reported. Drug loadwas determined by suspending a nominal 10 mg of microparticles in 8 mlHPLC grade methanol and sonicating for 2 hours. Samples were thencentrifuged at 14,000 g for 15 mins before an aliquot of the supernatantwas assayed via HPLC as described below. Corticosteroid-loadedmicroparticle samples, nominally 1 g were placed in 22 ml glass vials in8-20 ml of 0.5% v/v Tween 20 in 100 mM phosphate buffered saline andstored in a 37° C. incubator with magnetic stirring at 130 rpm. Eachtest sample was prepared and analyzed in duplicate to monitor possiblevariability. At each time point in the release study, microparticleswere allowed to settle, and an aliquot of between 4-1 6 ml ofsupernatant were taken, and replaced with an equal volume of fresh 0.5%v/v Tween 20 in 100 mM phosphate buffered saline. Drug load and in vitrorelease samples were analyzed by HPLC using a Hypersil C18 column (100mm, i.d. 5 mm, particle size 5 μm; ThermoFisher) and Beckman HPLC. Allsamples were run using a sample injection volume of 5 μm, and columntemperature of 40° C. An isocratic mobile phase of 60% methanol and 40%water was used at a flow rate of 1 ml/min, with detection at awavelength of 254 nm.

In one group of suitable thirty day formulations, the PLGA is an esterend capped PLGA (lactide: glycolide molar ratio of 75:25, inherentviscosity of 0.71 dL/g and molecular weight of 114 kDa) with 10% or 20%triblock (TB) polymer (PLGA-PEG-PLGA). Triblock polymer was synthesizedusing a method described by Zentner et al 2001 (Zentner et al.“Biodegradable block copolymers for delivery of proteins andwater-insoluble drugs.” J Control Release 72 (2001): 203-15) and refinedby Hou et al., 2008 (Hou et al., “In situ gelling hydrogelsincorporating microparticles as drug delivery carriers for regenerativemedicine.” J Pharm Sci 97(9) (2008): 3972-80). It is synthesized using aring opening polymerization of cyclic dimmers of D,L-lactide andglycolide with PEG 1,500 kDa in the presence of stannous octoate. Invitro release (lactide: glycolide molar ratio of 50:50, inherentviscosity of 0.40 dL/g and molecular weight of 66 kDa). The analyticalresults for these formulations are shown in Table 11.

TABLE 11 Analytical Results of Nominal 28.6% Triamcinolone Acetonide inPLGA 75:25 plus Triblock Microparticle Formulations PLGA (lactide:glycolide molar ratio ratio/ inherent viscosity/ Drug molecular loadIncor- weight/ (% poration target % TCA effi- In vitro TCA/ by ciencyParticle size release % PEG weight) (%) (Dv, μm ) (%) 75:25 ester 23.883.2 D0.1: 38.9 μm 1 day: 8.2 endcapped D0.5: 74.7 μm 2 day: 14.2 0.71dL/g D0.9: 103.0 μm 3 day: 15.7 114 kDa 4 day 18.2 28.6% 6 day: 28.8 TCA9 day: 38.9 10% 12 day: 49.8 Triblock 16 day: 61.6 20 day: 66.4 24 day:68.7 30 day: 72:3 35 day: 72.8 75:25 ester 24.8 86.7 D0.1: 39.5 μm 1day: 5.5 endcapped D0.5: 74.6 μm 2 day: 8.9 0.71 dL/g D0.9: 104.2 μm 3day: 12.8 114 kDa 4 day 14.5 28.6% TCA 6 day: 28.4 20% 9 day: 35.6Triblock 12 day: 47.8 (TB) 16 day: 53.0 20 day: 64.3 24 day: 67.3 30day: 73.0 35 day: 73.0

The in vitro cumulative release profiles for both triblock containingformulations are shown in FIG. 20. The amount of triblock in the testedformulations did not influence the cumulative percent release.

In one iteration of these data, the amount of TCA released per day wascalculated based on a human dose, as exemplified in Table 2, that mayachieve a temporary suppression of endogenous cortisol (greater than50%) and, within 14 days, achieve cortisol suppression of endogenouscortisol of less than 35%. These calculated doses equal 149 mg ofmicroparticles containing 35 mg of TCA and 252 microparticles containing62 mg of TCA, for the 10% and 20% triblock formulations respectively(FIG. 21 and FIG. 22). In a second iteration of these data, the amountof TCA released per day was calculated based on a human dose, asexemplified in Table 2, that would not have an suppress the HPA axis,i.e. endogenous cortisol suppression more than 35%. These calculateddoses equal 66 mg of microparticles containing 16 mg of TCA and 47microparticles containing 12 mg of TCA, for the 10% and 20% triblockformulations respectively (FIG. 23 and FIG. 24).

In another suitable formulation lasting greater than 30 days and up to90 days, the PLGA polymer consists of two different molecular weightPLGA 75:25 polymers in a two to one ratio, PLGA 75:25 (lactide:glycolide molar ratio of 75:25, inherent viscosity of 0.27 dL/g andmolecular weight of 29 kDa) and ester end capped PLGA 5.5 E (lactide:glycolide molar ratio of 75:25, inherent viscosity of 0.58 dL/g andmolecular weight of 86 kDa), respectively. The formulation was processedas described above with the exception that 200 mg of triamcinoloneacetonide was used in the formulation instead of 400 mg and similarlyanalyzed as describe for other formulations. The results are shown inthe Table 12.

TABLE 12 Analytical Results of a Nominal 16.7% Triamcinolone Acetonidein Mixed Molecular Weight PLGA 75:25 Microparticle Formulation PLGA(lactide: glycolide molar ratio ratio/ inherent viscosity/ Drugmolecular load Incor- weight/ (% poration target % TCA effi- In vitroTCA/ by ciency Particle size release % PEG weight) (%) (Dv, μm ) (%)75:25 ester 14.6 87.7 D0.1: 36.5 μm 1 day: 12.4 endcapped D0.5: 54.0 μm2 day: 21.6 0.58 dL/g D0.9: 69.4 μm 3 day: 27.3 86 kDa 4 day 33.6 And 6day: 41.2 75:25 9 day: 50.7 carboxylic 12 day: 54.3 acid 17 day: 62.0endcapped 20 day: 73.1 0.27 dL/g 25 day: 75.5 29 kDa 30 day: 82.9 16.7%35 day: 84.6 TCA 42 day: 87.4 49 day: 89.2

In vitro cumulative percent TCA release data is graphed in FIG. 25.

In one iteration of these in vitro release data, the amount of TCAreleased per day was calculated based on a human dose, as exemplified inTable 2, which may achieve a temporary suppression of endogenouscortisol (greater than 50%) and, within 14 days, achieve cortisolsuppression of endogenous cortisol of less than 35%. This calculateddose equals 317 mg of microparticles containing 46 mg of TCA. In asecond iteration of these data, the amount of TCA released per day wascalculated based on a human dose, as exemplified in Table 2, that wouldnot have an suppress the HPA axis, i.e. endogenous cortisol suppressionmore than 35%. This calculated dose equals 93 mg of microparticlescontaining 14 mg of TCA.

Several other triamcinolone acetonide PLGA depots were formulated in thesame manner as described above with different polymers includingpolycaprolactone (14 kDa), PLGA 50:50 (carboxylic acid end-capped, 0.44dL/g, MW 56 kDa), PLGA 85:15 (carboxylic acid end-capped, 0.43 dL/g, 56kDa) and a mixed molecular weight formulation using PLGA 75:25(carboxylic acid end capped, 0.27 dL/g, MW 29 kDa) and PLGA 75:25 (esterend-capped, 0.57 dL/g, MW 86 kDa) in a two to one ratio. The in vitrocumulative percent release of triamcinolone acetonide is shown in FIG.28. None of these formulations were suitable for a nominal thirty day orlonger duration pharmaceutical depot. Polycaprolactone release all thetriamcinolone acetonide prior to 14 days. The PLGA 50:50 microparticlesreleased about 35% of its content by day 12 and then entered a lag phasewhere no drug was released up to 30 days. The PLGA 85:15 microparticlesexhibited similar in vitro release kinetics as the PLGA 50:50,releasingabout 30% of its content by day 12 and then entered a lag phase where nodrug was released up to 30 days (See FIG. 28). A similar phenomenon isseen as shown in Example 4, where the mixed molecular weight PLGA 75:25unexpectedly exhibits faster initial release of the triamcinoloneacetonide than PLGA 50:50.

Based on the studies described herein, the Class B corticosteroidmicroparticle formulations, for example, the TCA microparticleformulations, exhibiting the desired release kinetics have the followingcharacteristics: (i) the corticosteroid is between 12%-28% of themicroparticle; and (ii) the polymer is (1) PLGA having a molecularweight in the range of about 40 to 70 kDa, having an inherent viscosityin the range of 0.3 to 0.5 dL/g, containing 10%-20% Triblock and/orhaving a lactide:glycolide molar ratio of 80:20 to 60:40 or (2) amixture of low and high molecular weight PLGAs in a two to one ratio.The low molecular weight PLGA has a molecular weight of range of 15-35kDa and an inherent viscosity range from 0.2 to 0.35 dL/g, and the highmolecular weight PLGA has a range of 70-95 kDa and an inherent viscosityrange of 0.5 to 0.70 dL/g.

Example 6 Preparation of Prednisolone PLGA Microparticles by Solid inOil in Water (S/O/W) Emulsion

A pharmaceutical depot was prepared comprised of the corticosteroid,prednisolone (PRED, 11β,17,21-trihydroxypregna-1,4-diene-3,20- dione)incorporated into microparticles in PLGA 50:50.

Formulations were prepared by dissolving approximately 1 gram of PLGA50:50 (lactide: glycolide molar ratio of 50:50, inherent viscosity 0.44dL/g, MW 56 kDa) in 6.67 mL of dichloromethane (DCM). To the polymersolution, 400 mg of prednisolone was added and sonicated. Subsequently,the corticosteroid containing dispersion was poured into 200 mL of 0.3%polyvinyl alcohol (PVA) solution while homogenizing with a Silversonhomogenizer using a rotor fixed with a Silverson Square Hole High ShearScreenTM, set to spin at 2,000 rpm to form the microparticles. After twominutes, the beaker was removed, and a glass magnetic stirrer) added tothe beaker, which was then placed onto a multi-way magnetic stirrer andstirred for four hours at 300 rpm to evaporate the DCM. Themicroparticles were then washed with 2 liters of distilled water, sievedthrough a 100 micron screen. The microparticles were then lyophilizedfor greater than 96 hours and vacuum packed.

Particle size of the PRED incorporated microparticles was determinedusing laser diffraction (Beckman Coulter LS 230) by dispersing a 50 mgaliquot in water, with the refractive index (RI) for water and PLGA, setat 1.33 and 1.46 respectively. The sample was stirred at the particlesize measurement measurements taken and the results reported. Drug loadwas determined by suspending a nominal 10 mg of microparticles in 8 mlHPLC grade methanol and sonicating for 2 hours. Samples were thencentrifuged at 14,000 g for 15 mins before an aliquot of the supernatantwas assayed via HPLC as described below. Corticosteroid-loadedmicroparticle samples, nominally 1 g were placed in 22 ml glass vials in8-20 ml of 0.5% v/v Tween 20 in 100 mM phosphate buffered saline andstored in a 37° C. incubator with magnetic stirring at 130 rpm. Eachtest sample was prepared and analyzed in duplicate to monitor possiblevariability. At each time point in the release study, microparticleswere allowed to settle, and an aliquot of between 4-1 6 ml ofsupernatant were taken, and replaced with an equal volume of fresh 0.5%v/v Tween 20 in 100 mM phosphate buffered saline. Drug load and in vitrorelease samples were analyzed by HPLC using a Hypersil C18 column (100mm, i.d. 5 mm, particle size 5 μm; ThermoFisher) and Beckman HPLC. Allsamples were run using a sample injection volume of 5 μm, and columntemperature of 40° C. An isocratic mobile phase of 60% methanol and 40%water was used at a flow rate of 1 ml/min, with detection at awavelength of 254 nm.The analytical results are shown in the Table 13.

TABLE 13 Analytical Results of a Nominal 28.6% Prednisolone in PLGA50:50 Microparticle Formulation PLGA (lactide: glycolide molar ratioratio/ inherent viscosity/ Drug molecular load Incor- weight/ (%poration target % PRED effi- In vitro TCA/ by ciency Particle sizerelease % PEG weight) (%) (Dv, μm ) (%) 50:50 19.0 66.4 D0.1: 34.4 μm 1day: 7.2 carboxylic D0.5: 66.9 μm 2 day: 11.5 acid D0.9: 87.5 μm 3 day:15.6 endcapped 4 day: 20.2 0.44 dL/g 5 day: 24.0 56 kDa 6 day: 28.428.6% 7 day: 32.7 PRED 9 day: 36.5 11 day: 41.4 13 day: 45.0 15 day:49.3 18 day: 52.0 21 day: 55.2 24 day: 58.3 27 day: 62.3 30 day: 65.9

In vitro release profile of the prednisolone PLGA microparticles isshown in FIG. 29. This formulation is suitable for a 30 day formulationor greater.

In one iteration of the cumulative percent in vitro release data, theamount of prednisolone released per day was calculated based on a humandose, as exemplified in Table 2, which may achieve a temporarysuppression of endogenous cortisol (greater than 50%) and, within 14days, achieve cortisol suppression of endogenous cortisol of less than35% (FIG. 30). The calculated dose equals 699 mg of microparticlescontaining 133 mg of PRED. In a second iteration of these data, theamount of PRED released per day was calculated based on a human dose, asexemplified in Table 2 that would not suppress the HPA axis, i.e.endogenous cortisol suppression of less than 35% (FIG. 31). Thiscalculated dose equals 377 mg of microparticles containing 72 mg ofPRED.

Based on the studies described herein, the Class A corticosteroidmicroparticle formulations, for example, the prednisolone microparticleformulations, exhibiting the desired release kinetics have the followingcharacteristics: (i) the corticosteroid is between 10%-40% of themicroparticle, for example, between 15%-30% of the microparticle; and(ii) the polymer is PLGA having a molecular weight in the range of about45 to 75 kDa, having an inherent viscosity in the range of 0.35 to 0.5dL/g, and or having a lactide:glycolide molar ratio of 60:40 to 45:55.

Example 7 Preparation of Betamethasone PLGA Microparticles by Solid inOil in Water (S/O/W) Emulsion

A pharmaceutical depot was prepared comprised of the corticosteroid,betamethasone (BETA,9-Fluoro-11β,17,21-trihydroxy-16β-methylpregna-1,4-diene-3,20-dione)incorporated into microparticles in PLGA 50:50.

A formulation was prepared by dissolving approximately 1 gram of PLGA50:50 (lactide: glycolide molar ratio of 50:50, inherent viscosity 0.44dL/g, MW 56 kDa) in 6.67 mL of dichloromethane (DCM). To the polymersolution, 400 mg of betamethasone was added and sonicated. Subsequently,the corticosteroid containing dispersion was poured into 200 mL of 0.3%polyvinyl alcohol (PVA) solution while homogenizing with a Silversonhomogenizer using a rotor fixed with a Silverson Square Hole High ShearScreen™, set to spin at 2,000 rpm to form the microparticles. After twominutes, the beaker was removed, and a glass magnetic stirrer) added tothe beaker, which was then placed onto a multi-way magnetic stirrer andstirred for four hours at 300 rpm to evaporate the DCM. Themicroparticles were then washed with 2 liters of distilled water, sievedthrough a 100 micron screen. The microparticles were then lyophilizedfor greater than 96 hours and vacuum packed.

Particle size of the BETA incorporated microparticles was determinedusing laser diffraction (Beckman Coulter LS 230) by dispersing a 50 mgaliquot in water, with the refractive index (RI) for water and PLGA, setat 1.33 and 1.46 respectively. The sample was stirred at the particlesize measurement measurements taken and the results reported. Drug loadwas determined by suspending a nominal 10 mg of microparticles in 8 mlHPLC grade methanol and sonicating for 2 hours. Samples were thencentrifuged at 14,000 g for 15 mins before an aliquot of the supernatantwas assayed via HPLC as described below. Corticosteroid-loadedmicroparticle samples, nominally 1 g were placed in 22 ml glass vials in8-20 ml of 0.5% v/v Tween 20 in 100 mM phosphate buffered saline andstored in a 37° C. incubator with magnetic stirring at 130 rpm. Eachtest sample was prepared and analyzed in duplicate to monitor possiblevariability. At each time point in the release study, microparticleswere allowed to settle, and an aliquot of between 4-1 6 ml ofsupernatant were taken, and replaced with an equal volume of fresh 0.5%v/v Tween 20 in 100 mM phosphate buffered saline. Drug load and in vitrorelease samples were analyzed by HPLC using a Hypersil C18 column (100mm, i.d. 5 mm, particle size 5 μm; ThermoFisher) and Beckman HPLC. Allsamples were run using a sample injection volume of 5 μm, and columntemperature of 40° C. An isocratic mobile phase of 60% methanol and 40%water was used at a flow rate of lml/min, with detection at a wavelengthof 254 nm. The analytical characteristics of the betamethasone PLGAmicroparticles are shown in the Table 14.

TABLE 14 Analytical Results of a Nominal 28.6% Betamethasone PLGA 50:50Microparticle Formulation PLGA( lactide: glycolide molar ratio DrugIncor- ratio/inherent load (% poration viscosity/molecular BETA effi- Invitro weight/target % by ciency Particle size release TCA/% PEG weight)(%) (Dv, μm ) (%) 50:50 carboxylic 22.8 79.7 D0.1: 42.1 μm 1 day: 2.0acid endcapped D0.5: 71.7 μm 2 day: 3.1 0.44 dL/g D0.9: 102.7 μm 3 day:4.8 56 kDa 4 day: 7.7 28.6% BETA 5 day: 12.5 6 day: 21.4 7 day: 30.8 9day: 38.6 11 day: 43.9 13 day: 49.6 15 day: 55.5 18 day: 57.5 21 day:59.2 24 day: 60.8 27 day: 62.9 30 day: 72.4

In vitro release profile of the betamethasone PLGA microparticles isshown in FIG. 32. This formulation is suitable for a 30 day formulationor greater.

In one iteration of the in vitro release data, the amount ofbetamethasone released per day was calculated based on a human dose, asexemplified in Table 2, which may achieve a temporary suppression ofendogenous cortisol (greater than 50%) and, within 14 days, achievecortisol suppression of endogenous cortisol of less than 35%. Thiscalculated dose equals 111 mg of microparticles containing 25 mg ofbetamethasone. In a second iteration of these data, the amount ofbetamethasone released per day was calculated based on a human dose, asexemplified in Table 2 that would not suppress the HPA axis, i.e.endogenous cortisol suppression never exceeding 35%. This calculateddose equals 38 mg of microparticles containing 9 mg of betamethasone.These doses are both graphically represented in FIGS. 33 and 34.

Based on the studies described herein, the Class C corticosteroidmicroparticle formulations, for example, the betamethasone microparticleformulations, exhibiting the desired release kinetics have the followingcharacteristics: (i) the corticosteroid is between 10%-40% of themicroparticle, for example, between 15%-30% of the microparticle; and(ii) the polymer is PLGA having a molecular weight in the range of about40 to 70 kDa, having an inherent viscosity in the range of 0.35 to 0.5dL/g, and or having a lactide:glycolide molar ratio of 60:40 to 45:55.

Example 8 Preparation of Fluticasone Propionate PLGA Microparticles bySolid in Oil in Water (S/O/W) Emulsion

A pharmaceutical depot was prepared comprised of the corticosteroid,fluticasone propionate (FLUT, S-(fluoromethyl)6α,9-difluoro-11β,17-dihydroxy-16α-methyl-3-oxoandrosta-1,4-diene-17β-carbothioate,17-propionate) incorporated into microparticles in PLGA 50:50.

A formulation was prepared by dissolving approximately 1 gram of PLGA50:50 (lactide: glycolide molar ratio of 50:50, inherent viscosity 0.45dL/g, molecular weight 66 kDa) in 6.67 mL of dichloromethane (DCM). Tothe polymer solution, 200 mg of fluticasone propionate was added andsonicated. Subsequently, the corticosteroid containing dispersion waspoured into 200 mL of 0.3% polyvinyl alcohol (PVA) solution whilehomogenizing with a Silverson homogenizer using a rotor fixed with aSilverson Square Hole High Shear ScreenTM set to spin at 2,000 rpm toform the microparticles. After two minutes, the beaker was removed, anda glass magnetic stirrer) added to the beaker, which was then placedonto a multi-way magnetic stirrer and stirred for four hours at 300 rpmto evaporate the DCM. The microparticles were then washed with 2 litersof distilled water, sieved through a 100 micron screen. Themicroparticles were then lyophilized for greater than 96 hours andvacuum packed.

Particle size of the FLUT incorporated microparticles was determinedusing laser diffraction (Beckman Coulter LS 230) by dispersing a 50 mgaliquot in water, with the refractive index (RI) for water and PLGA, setat 1.33 and 1.46 respectively. The sample was stirred at the particlesize measurement measurements taken and the results reported. Drug loadwas determined by suspending a nominal 10 mg of microparticles in 8 mlHPLC grade methanol and sonicating for 2 hours. Samples were thencentrifuged at 14,000 g for 15 mins before an aliquot of the supernatantwas assayed via HPLC as described below. Corticosteroid-loadedmicroparticle samples, nominally 1 g were placed in 22 ml glass vials in8-20 ml of 0.5% v/v Tween 20 in 100 mM phosphate buffered saline andstored in a 37° C. incubator with magnetic stirring at 130 rpm. Eachtest sample was prepared and analyzed in duplicate to monitor possiblevariability. At each time point in the release study, microparticleswere allowed to settle, and an aliquot of between 4-1 6 ml ofsupernatant were taken, and replaced with an equal volume of fresh 0.5%v/v Tween 20 in 100 mM phosphate buffered saline. Drug load and in vitrorelease samples were analyzed by HPLC using a Hypersil C18 column (100mm, i.d. 5 mm, particle size 5 μm; ThermoFisher) and Beckman HPLC. Allsamples were run using a sample injection volume of 5 μm, and columntemperature of 40° C. An isocratic mobile phase of 60% methanol and 40%water was used at a flow rate of 1 ml/min, with detection at awavelength of 254 nm.Theanalytical results of the fluticasone propionatePLGA microparticles are shown in Table 15.

TABLE 15 Analytical Results of a Nominal 16.7% Fluticasone PLGA 50:50Microparticle Formulation PLGA (lactide: glycolide molar ratio ratio/inherent viscosity/ Drug Incor- molecular load (% poration weight/ FLUTeffi- In vitro target % by ciency Particle size release FLUT/ weight)(%) (Dv, μm) (%) 50:50 8.5 51.1 D0.1: 34.1 μm 1 day: 29.5 carboxylicD0.5: 65.5 μm 2 day: 43.5 acid D0.9: 95.0 μm 3 day: 46.7 endcapped 4day: 50.9 0.45 dL/g 5 day: 55.5 66 kDa 6 day: 58.6 16.7% FLUT 7 day:60.1 9 day: 63 11 day: 66.8 13 day: 67.8 15 day: 68.7 18 day: 73.7 21day: 81.8 24 day: 93.7 26 day: 97.1 31 day: 100.8

In vitro release profile of the fluticasone propionate PLGAmicroparticles is shown in FIG. 35. This formulation is suitable for a30 day formulation or greater.

In one iteration of the in vitro release data, the amount of fluticasonepropionate released per day was calculated based on a human dose, asexemplified in Table 2, which may achieve a temporary suppression ofendogenous cortisol (greater than 50%) and, within 14 days, achievecortisol suppression of endogenous cortisol of less than 35%. Thiscalculated dose equals 178 mg of microparticles containing 15 mg offluticasone propionate. In a second iteration of these data, the amountof fluticasone propionate released per day was calculated based on ahuman dose, as exemplified in Table 2 that would not suppress the HPAaxis, i.e. endogenous cortisol suppression never exceeding 35%. Thiscalculated dose equals 24 mg of microparticles containing 2 mg offluticasone propionate. These doses are both graphically represented inFIGS. 36 and 37.

Other fluticasone propionate PLGA depots were formulated in the samemanner as described above with different PLGA polymers or amountsfluticasone propionate. In one formulation, a PLGA polymer with a higherlactide to glycolide ratio (PLGA 75:25 (ester end-capped PLGA 75:25,lactide: glycolide molar ratio of 75:25, 0.58 dL/g, MW 86 kDa) was usedinstead of the PLGA 50:50 as previously described. Unlike thetriamcinolone acetonide preparations described in Example 5, buttypically expected as described in the literature, the higher lactide toglycolide ratio resulted in a slower release, where 30% release in 14days, followed by a substantial lag phase where little drug is releasedfor a minimum of thirty days. In another example, 400 mg of fluticasonepropionate instead of 200 mg was used in preparation of PLGA 50:50microparticles (target drug load 28.6%). Unlike triamcinolone acetonidemicroparticle preparations, the higher drug load did not result in asignificantly different release of fluticasone propionate; FIG. 38 showsthe in vitro release of all three fluticasone propionate formulations.

Based on the studies described herein, the Class D corticosteroidmicroparticle formulations, for example, the fluticasone or fluticasonepropionate microparticle formulations, exhibiting the desired releasekinetics have the following characteristics: (i) the corticosteroid isbetween 8%-20% of the microparticle, and (ii) the polymer is PLGA havinga molecular weight in the range of about 40 to 70 kDa, having aninherent viscosity in the range of 0.35 to 0.5 dL/g, and or having alactide:glycolide molar ratio of 60:40 to 45:55.

Example 9 Preparation of Dexamethasone Microparticles by SolventDispersion in PLGA

A pharmaceutical depot was prepared comprised of the corticosteroid,dexamethasone (DEX,9-Fluoro-11β,17,21-trihydroxy-16α-methylpregna-1,4-diene-3,20-dione)incorporated into microparticles in PLGA 50:50.

A formulation was prepared by dissolving approximately 1 gram of PLGA50:50 (lactide: glycolide molar ratio of 50:50, inherent viscosity 0.45dL/g, molecular weight 66 kDa) in 6.67 mL of dichloromethane (DCM). Tothe polymer solution, 200 mg of dexamethasone was added and sonicated.Subsequently, the corticosteroid containing dispersion was poured into200 mL of 0.3% polyvinyl alcohol (PVA) solution while homogenizing witha Silverson homogenizer using a rotor fixed with a Silverson Square HoleHigh Shear ScreenTM, set to spin at 2,000 rpm to form themicroparticles. After two minutes, the beaker was removed, and a glassmagnetic stirrer) added to the beaker, which was then placed onto amulti-way magnetic stirrer and stirred for four hours at 300 rpm toevaporate the DCM. The microparticles were then washed with 2 liters ofdistilled water, sieved through a 100 micron screen. The microparticleswere then lyophilized for greater than 96 hours and vacuum packed.

Particle size of the DEX incorporated microparticles was determinedusing laser diffraction (Beckman Coulter LS 230) by dispersing a 50 mgaliquot in water, with the refractive index (RI) for water and PLGA, setat 1.33 and 1.46 respectively. The sample was stirred at the particlesize measurement measurements taken and the results reported. Drug loadwas determined by suspending a nominal 10 mg of microparticles in 8 mlHPLC grade methanol and sonicating for 2 hours. Samples were thencentrifuged at 14,000 g for 15 mins before an aliquot of the supernatantwas assayed via HPLC as described below. Corticosteroid-loadedmicroparticle samples, nominally 1 g were placed in 22 ml glass vials in8-20 ml of 0.5% v/v Tween 20 in 100 mM phosphate buffered saline andstored in a 37° C. incubator with magnetic stirring at 130 rpm. Eachtest sample was prepared and analyzed in duplicate to monitor possiblevariability. At each time point in the release study, microparticleswere allowed to settle, and an aliquot of between 4-1 6 ml ofsupernatant were taken, and replaced with an equal volume of fresh 0.5%v/v Tween 20 in 100 mM phosphate buffered saline. Drug load and in vitrorelease samples were analyzed by HPLC using a Hypersil C18 column (100mm, i.d. 5 mm, particle size 5 μm; ThermoFisher) and Beckman HPLC. Allsamples were run using a sample injection volume of 5 μm, and columntemperature of 40° C. An isocratic mobile phase of 60% methanol and 40%water was used at a flow rate of 1 ml/min, with detection at awavelength of 254 nm. The analytical results for the dexamethasone PLGAmicroparticles are shown in Table 16.

TABLE 16 Analytical Results of a Nominal 28.6% Dexamethasone PLGA 50:50Microparticle Formulation PLGA (lactide: glycolide molar ratio Incor-ratio/inherent Drug poration viscosity/molecular load (% effi- In vitroweight/target % DEX by ciency Particle size release FLUT/ weight) (%)(Dv, μm ) (%) 50:50 carboxylic 22.1 77.2 D0.1: 41.2 μm 1 day: 2.9 acidendcapped D0.5: 71.9 μm 2 day: 4.6 0.45 dL/g D0.9: 99.1 μm 3 day: 6.3 66kDa 4 day: 8.7 28.6% DEX 5 day: 10.9 6 day: 12.7 7 day: 15.0 9 day: 16.411 day: 18.0 13 day: 20.7 15 day: 24.6 18 day: 26.2 21 day: 28.1 24 day:30.3 27 day: 34.0 30 day: 46.3

In vitro cumulative percent release of the dexamethasone is shown in 39,and results in suitable formulation for a minimum of thirty days and,assuming linear release, likely up to 60 days.

In one iteration of the in vitro release data, the amount ofdexamethasone released per day was calculated based on a human dose, asexemplified in Table 2, which may achieve a temporary suppression ofendogenous cortisol (greater than 50%) and, within 14 days, achievecortisol suppression of endogenous cortisol of less than 35%. In asecond iteration of these data, the amount of dexamethasone released perday was calculated based on a human dose, as exemplified in Table 2 thatwould not suppress the HPA axis, i.e. endogenous cortisol suppressionnever exceeding 35%. In the case of dexamethasone, where the data istruncated, both calculated human doses are the same; 36 mg ofmicroparticles containing 8 mg of dexamethasone. The doses aregraphically represented in FIG. 40.

Example 10 Pharmacology, Pharmacokinetics and Exploratory Safety Studyof Corticosteroid Formulations

In an exploratory safety study in rats, single intra-articular (IA)dosesof TCA immediate release (TCA IR) (0.18 and 1.125 mg) and doses of TCAin 75:25 PLGA formulation microparticles (FX006) (0.28, 0.56 and 1.125mg (i.e., the maximum feasible dose) of TCA) were evaluated. Bloodsamples were collected at various time points for determination ofplasma concentrations. Plasma concentration-time data from this studyand pharmacokinetic (PK) analysis thereof are shown in FIGS. 41-43 andTables 17-20.

As seen in FIGS. 41A-41D, FX006 dosed at 1.125 mg resulted in a veryslow absorption of TCA in the systemic circulation and a markedly lowerC_(max) as compared to TCA IR.

As shown in Table 17, the mean AUC₀₋₄ values of TCA following 1.125 mgadministration of FX006 were 2.1-fold lower than those observed for TCAIR (i.e., 2856 vs. 6065 ng.h/mL, respectively). The mean C_(max) valuesof TCA following 1.125 mg administration of FX006 were 15-fold lowerthan those observed for TCA IR (i.e., 125 vs. 8.15 ng/mL, respectively).The absorption of TCA following administration of FX006 was slower thanthat observed for TCA IR, with mean T_(max) values observed at 3.33 and1.00 h, respectively. The elimination half-life of TCA followingadministration of 1.125 mg FX006 and TCA IR were 451 and 107 h,respectively.

The above results suggest a slower distribution and bioavailability ofTCA in the systemic circulation following administration of FX006 ascompared to TCA IR. Without wishing to be bound by theory, the slowerdistribution FX006 into the systemic circulation may be related to thelonger residence time of FX006 at the site of injection. This issupported by the lesser availability of the FX006 microparticleformulation in the early “burst” phase, where only 4-9% of product isreleased, compared to at least 23% of the IR product.

Bioavailability of TCA in the systemic circulation followingadministration of FX006 was 3-fold lower than that observed for TCA IR,as shown in Table 18.

TABLE 18 Bioavailability of TCA in Plasma Absolute BioavailabilityComparison FX006 (0.28 mg) TCA IR (0.18 mg) F_(abs) (%) 17.9 58.6

For the 0.56 and 1.125 mg dose levels of FX006, apparent F% were 23.1%and 58.1%, respectively. The IV data in rats shown in Table 19 was usedas a reference to calculate F.

TABLE 19 Pharmacokinetic Parameters of TCA in Rat Plasma After i.v. (50mg/kg bolus + 23 mg/kg/h Infusion) Administration of TriamcinoloneAcetonide Phosphate Parameter Rat 1 Rat 2 Rat 3 Mean ± SD V_(c) (L/kg)0.684 0.856 1.29 0.944 ± 0.314 CL (L/h/kg) 1.15 0.790 0.872 0.937 ±0.188 k₁₂ (h¹) 1.64 1.79 1.59 11.67 ± 0.102 k₂₁ (h¹) 1.04 0.640 1.130.937 ± 0.261 T_(1/2β) (h) 1.55 3.71 2.87 2.71 ± 1.09 ƒ_(u) 0.084 0.1100.085 0.093 ± 0.015

from Rojas et al., “Microdialysis of triamcinolone acetonide in ratmuscle.” J Pharm Sci 92(2) (2003):394-397.

The initial “burst” (i.e., exposure up to 24 h) accounted for less than10% of the total systemic exposure of FX006. The initial burst accountedfor ˜23-62% of the total exposure for the TCA IR product, as shown inTable 20.

TABLE 20 Relative Availability of TCA in Plasma (Initial Burst vs.Delayed Release) Treatment FX006 FX006 FX006 TCA IR TCA IR (0.28 mg)(0.56 mg) (1.125 mg) (0.18 mg) (1.125 mg) Variable Mean Mean Mean MeanMean AUC₀₋₂₄ 31.0 33.0 136 297 1403 (ng.h/mL) AUC_(0-∞) 356 572 2856 4796065 (ng.h/mL) AUC_(24-∞) 325 539 2720 182 4662 (ng.h/mL) % Initial 8.695.76 4.76 62.1 23.1 Burst

In this same study, groups of animals were sacrificed 28 days afterdosing, and the remaining were terminated on Day 42. Body weights weremonitored throughout the study and key organs (spleen, adrenal glands,thymus) were weighed upon necropsy. The injected knee and thecontralateral control joints were prepared for histological assessment.Toluidine blue stained sections of joints were evaluated fortreatment-related alterations. Histologic changes were described,wherever possible, according to their distribution, severity, andmorphologic character.

Histological analysis demonstrated the following observations. First,injected joints from placebo (blank PLGA microspheres)-treated animalshad minimal multifocal macrophage infiltration in associated with 20-130μm diameter microspheres, whereas none of the active FX006-injectedjoints showed the presence of any microspheres at Day 28.Placebo-treated rat joints had no cartilage or joint changes save forthe presence of spontaneous cartilage cysts in a few joints (1 at Day28, 2 at Day 42) in the right (injected) knees. The left knees in theplacebo-treated rat joints were normal. In comparison, both knees in thehigh dose TCA IR and the high and mid-dose FX006 -groups showed somemild bone marrow hypocellularity and growth plate atrophy (dosedependent for FX006). Both knees in the low dose TCA IR and FX006animals were normal. Spontaneous cartilage cysts noted in placeboanimals were also noted in all groups dosed with FX006 with no increasein incidence or severity. High dose TCA IR increased cartilage cysts atDay 42 but not at Day 28. In general, FX006-treated animals had normalarticular cartilage despite the presence of catabolic effects on otherjoint structures, which was likely more readily observed on account ofthe young age of the animals.

Overall, all observed effects of FX006, especially at the high dose,such as body weight loss and reduced organ weights were also seen withTCA IR. The time course of inhibition of the HPA axis (measured ascorticosterone levels) is shown in FIG. 42. It should be noted that atthe lowest dose of FX006 (0.28 mg; circles) corticosterone levels wereinitially inhibited but recovered back to near baseline by Day 14post-dose. Similarly, with TCA IR at the lowest dose (0.18 mg),corticosterone levels recovered by Day 7 (squares). With the mid (0.56mg) and high (1.125 mg) doses of FX006 and the high dose of TCA IR(1.125 mg), corticosterone levels were inhibited longer as shown in FIG.42.

A PK-PD analysis demonstrated that inhibition of corticosterone wascorrelated with systemic TCA levels and followed a classical inhibitorymodel as shown in FIG. 43. The IC₅₀ was about 1 ng/mL and the E_(max)was achieved at 50-80 ng/mL.

Example 11 Evaluation of Efficacy of Single Doses of TCA ImmediateRelease and TCA Microparticle Formulation in Animal Model ofOsteoarthritis

The studies described herein were designed to test and evaluate theefficacy of the corticosteroid microparticle formulations providedherein as compared to immediate release corticosteroid formulations.While the studies herein use TCA, it is understood that othercorticosteroids, including other Class B corticosteroids, Class Acorticosteroids, Class C corticosteroids, and Class D corticosteroids,can be evaluated using these materials, methods and animal models.

Efficacy of single intra-articular (IA) doses of FX006 (TCA in 75:25PLGA formulation microparticles) and TCA IR (immediate release) wasevaluated in a rat model of osteoarthritis of the knee via sensitizationand challenge by peptidoglycan polysaccharide (PGPS). The model involvespriming the animals with an intra-articular injection of PGPS in theright knee. The following day, any animals with no knee discomfort wereeliminated from the test article groups and placed into the baselinegroup. Two weeks later, knee inflammation was reactivated by a tail veininjection of PGPS, 2.5 hr following IA dosing with FX006 or TCA IR atthe doses selected (n=10/group). Differences in weight-bearing and gait(as a measure of joint pain experienced by the animals), histopathology,plasma PK etc. were evaluated.

Doses of FX006 (0.28, 0.12, 0.03 mg) and TCA IR (0.06, 0.03 mg) for thisstudy were selected based on data from the study described above inExample 10 and an initial run of the PGPS model in which only TCA IR wasevaluated at two IA dose levels. The goals of the present study were todemonstrate the following:

-   -   FX006 is efficacious at doses that do not inhibit the HPA axis    -   The duration of efficacy is a function of dose    -   FX006 provides more prolonged pain relief as compared to TCA        IR—Since only about 10% of the TCA payload is expected to be        released from FX006 in the first 24 hr, one TCA IR dose group        (0.03 mg) was chosen to match 10% of the TCA in FX006 at a dose        of 0.28 mg    -   Effects of matched doses of FX006 and TCA IR (0.03 mg)

The duration of efficacy was assessed by 3 different reactivations, 2weeks apart. After that point, the arthritis observed in the animalsbecomes more wide-spread making the efficacy in the index knee moredifficult to assess.

At the first reactivation, vehicle treated animals demonstrate painfulgait as demonstrated by high pain scores (3.5 out of a maximum of 4possible) as shown in FIGS. 44A, 44B, and 44C. FX006 at 0.28 mg(squares) showed good efficacy. In the previous study described inExample 10, this dose was demonstrated to inhibit the HPA axisimmediately after dosing but a return to baseline function wasdemonstrated by Day 14. Interestingly, this dose of FX006 continued tobe efficacious upon the 2^(nd) and 3^(rd) reactivations on Days 14 and28 when the HPA axis function was presumably normal. It should also benoted that since HPA axis function returned to baseline by Day 7 at a0.18 mg dose of TCA IR in the previous study described in Example 10,the effects of the doses of TCA IR used in the present study (0.06 and0.03 mg) were also in the presence of normal HPA axis function followingan initial transient inhibition. Corticosterone measurements from thepresent study (as an indicator of HPA axis function) are presented aschange from baseline for each treatment group in FIG. 46. Asdemonstrated from these data, corticosterone levels for all groupsrecovered by Day 14; hence the goal of prolonged efficacy with FX006 inthe presence of normal HPA axis function was achieved.

Overall, a clear dose-dependence of response was noted for both FX006and TCA IR. Also, if less than 10% of this dose is available by the dayafter dosing (Day 1), it should be noted in FIG. 44B that the efficacyof FX006 at 0.28 mg (squares) is greater than TCA IR at 0.03 mg(triangles) at all evaluations. Further, the duration of efficacy of TCA(both FX006 and IR) appears to be a function of dose, however, theprolonged release of TCA from the PLGA microspheres in FX006 results inmore sustained efficacy. This is more clearly depicted in anotherrepresentation of the data in FIG. 45 in which peak response for eachdose as determined by gait/pain scores on Day 1 following eachreactivation (Days 1, 15 and 29) are plotted. FIG. 46 plots the timecourse of corticosterone recovery for all study groups. On balance,across all groups that received the corticosteroid, there was recovery.

Plasma levels of TCA were measured in samples taken from all rats atbaseline (Day-4), Days 0 (2 hr post dosing), 1, 3, 8, 14, 17, 21, 28,and 31. Concentration-time curves for all treatment groups are shown inFIG. 47A. FIG. 47B shows only the FX006 dose groups on a larger scalesince maximal plasma concentrations with FX006 were far lower than thosewith TCA IR.

Histopathological evaluation of the knees taken from all animals at theend of the study (Day 32 at the end of the 3^(rd) reactivation ofarthritis) demonstrated statistically significant improvement by FX006at the high and mid-range doses (0.28 and 0.12 mg) in the compositehistological score and each component score (inflammation, pannus,cartilage damage and bone resorption) as shown in FIG. 48. As describedabove, the dose of 0.28 mg FX006 demonstrated strong efficacy (i.e.analgesic activity) throughout all 3 reactivations, whereas the dose of0.12 mg was active but to a lesser degree through all 3 reactivations.At the doses of TCA IR used, the duration of efficacy was mostly throughthe first reactivation of arthritis, with partial efficacy of the higher(0.06 mg) dose in the second reactivation, and this also translated intoa much smaller non-significant improvement in histological scores.Importantly, these data demonstrate that TCA has no deleterious effecton cartilage and as has been described in other settings, it actuallyreduces cartilage damage in an inflammatory milieu.

In conclusion, the prolonged residence of TCA in the joint upon IAdosing with FX006 resulted in extending the duration of efficacy in therat PGPS model of arthritis with a significant histological improvementin inflammation, pannus formation, cartilage damage and bone resorption.FX006 had these effects without inhibiting HPA axis function asdemonstrated by the return to baseline of corticosterone levels within14 days after dosing. The clinical implications for the treatment ofpatients with osteoarthritis, rheumatoid arthritis and otherinflammatory joint disorders are as follows:

-   -   Intra-articular injection of sustained release corticosteroid        microparticle formulations provides prolonged pain relief        relative to intra-articular injection of immediate release        steroids.    -   Intra-articular injection of sustained release corticosteroid        microparticle formulations is efficacious in reducing pain and        inflammation at doses that do not inhibit the HPA axis.    -   The duration of efficacy of sustained release of intra-articular        corticosteroid microparticle formulations is a function of dose.    -   Intra-articular injection of sustained release corticosteroid        microparticle formulations slows, arrests, reverses, or        otherwise inhibits structural damage to tissues caused by        inflammation.

Although particular embodiments have been disclosed herein in detail,this has been done by way of example for purposes of illustration only,and is not intended to be limiting with respect to the scope of theappended claims, which follow. In particular, it is contemplated by theinventors that various substitutions, alterations, and modifications maybe made to the invention without departing from the spirit and scope ofthe invention as defined by the claims. Other aspects, advantages, andmodifications are considered to be within the scope of the followingclaims. The claims presented are representative of the inventionsdisclosed herein. Other, unclaimed inventions are also contemplated.Applicants reserve the right to pursue such inventions in later claims.

What is claimed is:
 1. A formulation comprising controlled- orsustained-release microparticles comprising a combination of acorticosteroid and a lactic acid-glycolic acid copolymer matrix selectedfrom the group consisting of: (a) controlled- or sustained-releasemicroparticles comprising a Class B corticosteroid and a lacticacid-glycolic acid copolymer matrix, wherein the Class B corticosteroidcomprises between 22% to 28% of the microparticles and wherein thelactic acid-glycolic acid copolymer has one of more of the followingcharacteristics: (i) a molecular weight in the range of about 40 to 70kDa; (ii) an inherent viscosity in the range of 0.3 to 0.5 dL/g; or(iii) a lactide:glycolide molar ratio of 80:20 to 60:40; (b) controlled-or sustained-release microparticles comprising a Class A corticosteroidand a lactic acid-glycolic acid copolymer matrix, wherein the Class Acorticosteroid comprises between 15% to 30% of the microparticles andwherein the lactic acid-glycolic acid copolymer has one of more of thefollowing characteristics: (i) a molecular weight in the range of about40 to 70 kDa; (ii) an inherent viscosity in the range of 0.35 to 0.5dL/g; or (iii) a lactide:glycolide molar ratio of 60:40 to 45:55; (c)controlled- or sustained-release microparticles comprising a Class Ccorticosteroid and a lactic acid-glycolic acid copolymer matrix, whereinthe Class C corticosteroid comprises between 15% to 30% of themicroparticles and wherein the lactic acid-glycolic acid copolymer hasone of more of the following characteristics: (i) a molecular weight inthe range of about 40 to 70 kDa; (ii) an inherent viscosity in the rangeof 0.35 to 0.5 dL/g; or (iii) a lactide:glycolide molar ratio of 60:40to 45:55; and (d) controlled- or sustained-release microparticlescomprising a Class D corticosteroid and a lactic acid-glycolic acidcopolymer matrix, wherein the Class D corticosteroid comprises between8% to 20% of the microparticles and wherein the lactic acid-glycolicacid copolymer has one of more of the following characteristics: (i) amolecular weight in the range of about 40 to 70 kDa; (ii) an inherentviscosity in the range of 0.35 to 0.5 dL/g; or (iii) a lactide:glycolidemolar ratio of 60:40 to 45:55.
 2. The formulation of claim 1, whereinthe copolymer is biodegradable.
 3. The formulation of claim 1, whereinthe lactic acid-glycolic acid copolymer is a poly(lactic-co-glycolic)acid copolymer (PLGA).
 4. The formulation of claim 1, wherein the ClassB corticosteroid is triamcinolone acetonide or a commercially availablechemical analogue or a pharmaceutically-acceptable salt thereof.
 5. Theformulation of claim 1, wherein the Class A corticosteroid isprednisolone or a commercially available chemical analogue or apharmaceutically-acceptable salt thereof.
 6. The formulation of claim 1,wherein the Class C corticosteroid is betamethasone or a commerciallyavailable chemical analogue or a pharmaceutically-acceptable saltthereof.
 7. The formulation of claim 1, wherein the Class Dcorticosteroid is fluticasone propionate, fluticasone, or a commerciallyavailable chemical analogue or a pharmaceutically-acceptable saltthereof.
 8. The formulation of claim 1, wherein the microparticles havea mean diameter of between 10 μm to 100 μm.
 9. The formulation of claim1, wherein the corticosteroid is a Class B corticosteroid, and whereinthe lactic acid-glycolic acid copolymer has a molar ratio of lacticacid: glycolic acid from the range of about 80:20 to 60:40.
 10. Theformulation of claim 1, wherein the corticosteroid is a Class Bcorticosteroid, and wherein the lactic acid-glycolic acid copolymer hasa molar ratio of lactic acid: glycolic acid of 75:25.
 11. Theformulation of claim 1, wherein the corticosteroid is a Class Acorticosteroid, and wherein the lactic acid-glycolic acid copolymer hasa molar ratio of lactic acid: glycolic acid from the range of about60:40 to 45:55.
 12. The formulation of claim 1, wherein thecorticosteroid is a Class A corticosteroid, and wherein the lacticacid-glycolic acid copolymer has a molar ratio of lactic acid: glycolicacid of 50:50.
 13. The formulation of claim 1, wherein thecorticosteroid is a Class C corticosteroid, and wherein the lacticacid-glycolic acid copolymer has a molar ratio of lactic acid: glycolicacid from the range of about 60:40 to 45:55.
 14. The formulation ofclaim 1, wherein the corticosteroid is a Class C corticosteroid, andwherein the lactic acid-glycolic acid copolymer has a molar ratio oflactic acid: glycolic acid of 50:50.
 15. The formulation of claim 1,wherein the corticosteroid is a Class D corticosteroid, and wherein thelactic acid-glycolic acid copolymer has a molar ratio of lactic acid:glycolic acid from the range of about 60:40 to 45:55.
 16. Theformulation of claim 1, wherein the corticosteroid is a Class Dcorticosteroid, and wherein the lactic acid-glycolic acid copolymer hasa molar ratio of lactic acid: glycolic acid of 50:50.
 17. Theformulation of claim 1, wherein the microparticles further comprise apolyethylene glycol (PEG) moiety, wherein the PEG moiety comprisesbetween 25% to 0% weight percent of the microparticle.
 18. Theformulation of claim 1, wherein the corticosteroid is released forbetween 14 days and 90 days.
 19. A method of treating pain orinflammation in a patient comprising administering to said patient atherapeutically effective amount of the formulation of claim
 1. 20. Themethod of claim 19, wherein the formulation releases the corticosteroidfor at least 14 days at a rate that does not adversely suppress thehypothalamic-pituitary-adrenal axis (HPA axis).
 21. The method of claim19, wherein the formulation is administered as one or more injections.22. The method of claim 19, wherein the patient has osteoarthritis,rheumatoid arthritis, acute gouty arthritis, or synovitis.
 23. A methodof slowing, arresting or reversing progressive structural tissue damageassociated with chronic inflammatory disease in a patient comprisingadministering to said patient a therapeutically effective amount of theformulation of claim
 1. 24. The method of claim 23, wherein theformulation releases the corticosteroid for at least 14 days at a ratethat does not adversely suppress the hypothalamic-pituitary-adrenal axis(HPA axis).
 25. The method of claim 23, wherein the formulation isadministered as one or more injections.
 26. The method of claim 23,wherein the patient has osteoarthritis, rheumatoid arthritis, acutegouty arthritis, or synovitis.
 27. A method of manufacturing theformulation of claim 1, wherein the microparticles are manufacturedusing a solvent evaporation process wherein the Class B corticosteroidis dispersed in a lactic acid-glycolic acid copolymer organic solutionand the mixture is treated to remove the solvent from the mixture,thereby producing microparticles.
 28. The method of manufacture of claim27, wherein the solvent evaporation process utilizes a spray drying orfluid bed apparatus to remove the solvent and produce microparticles.29. The method of manufacture of claim 27, wherein the solventevaporation process utilizes a spinning disk.
 30. A method ofmanufacturing the formulation of claim 1, wherein the microparticles aremanufactured using a solid in oil in water emulsion process wherein theClass A corticosteroid is dispersed in a lactic acid-glycolic acidcopolymer organic solution and added to an aqueous solvent to producemicroparticles.
 31. A method of manufacturing the formulation of claim1, wherein the microparticles are manufactured using a solid in oil inwater emulsion process wherein the Class C corticosteroid is dispersedin a lactic acid-glycolic acid copolymer organic solution and added toan aqueous solvent to produce microparticles.
 32. A method ofmanufacturing the formulation of claim 1, wherein the microparticles aremanufactured using a solid in oil in water emulsion process wherein theClass D corticosteroid is dispersed in a lactic acid-glycolic acidcopolymer organic solution and added to an aqueous solvent producemicroparticles.